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Archive 1Archive 2Archive 3

Formation of Elements

From the first paragraph: "Almost all elements heavier than hydrogen and helium were created inside the cores of stars." Almost? What does almost mean? Is this referring to the infinitesimally small amount of Lithium and Beryllium formed around the start of the Big Bang, or is there some other way certain heavier elements are formed? —Preceding unsigned comment added by 131.191.95.151 (talk) 00:21, 22 December 2007 (UTC)

Definition

There is a conflict between the definition of star at the head of the article and the linked article on white dwarf. The definition here (which makes nuclear fusion a prerequisite) would deny a white dwarf the status of being a star, but the linked article states unequivocally that a white dwarf is a star. The balance of this article seems to take care to avoid contradicting its own definition.

This is a tricky one to resolve. One way might be to adopt the historical approach:


Historically, the word star (or a word of which it is a translation) meant a fixed star - any one of the large number of point-like light sources visible in the night sky and sharing a single common daily apparent motion. The science of astronomy has revealed that all such stars are ...
As astronomical discoveries have been made the precise boundaries of the catgegory of stars have come into dispute, on the basis of the inferred history and the current state of particular objects. -- Alan Peakall 13:56 Feb 18, 2003 (UTC)
The definition is too technical. I imagine a third-grader researching about stars would find all the physics terms confusing. Is there a way to get a kid-friendly (or even a high-school-friendly) definition that is still accurate? —seav 11:46 15 Jul 2003 (UTC)
Stars appear, upon the celestial sphere, as twinkling points of light.
is as simple as I could go
Okay, I tried a more general introduction. Comment and edit as needed. :) —seav 23:24 16 Jul 2003 (UTC)

I think that the section 'Nuclear fusion reaction pathways' deserve it's own article looxix 19:26 Mar 2, 2003 (UTC)

The opening paragraph links to both disc and outer space, which don't seem to be very relevant. Could someone make a more relevant article on disc ("the sun appears as a disc")? Also, I'm sure that outer space can also have its own article, and not just a redirect to space science. I seem to recall that outer space is defined as the region above an imaginary boundary several kilometers from the surface of the earth. Below that is the inner space/atmosphere? —seav 08:15 19 Jul 2003 (UTC)

In answer to AstroNomer's question, I remarked the other day that Mars was the brightest "star" in the sky, causing no confusion or disagreement among my audience. (Instead we started talking about the relative apparent magnitude of various planets, ultimately looking things up on Wikipedia. ^_^) I also regularly refer to meteors as "falling stars", which seems so much more romantic. Of course, I recognise the imprecision of such language (which I don't use when discussing astronomy); naturally this deserves nothing more in the article that a mention in passing of colloquial usage -- which is what it has. -- Toby Bartels 04:32, 8 Sep 2003 (UTC)

The article also refers to stars as "gaseous", whereas astronomers and astrophysicists frequently refer to various things as "stars" that are in states of matter rather more exotic than what we usually consider gaseous (neutron stars, hypothetical strange-matter stars, etc.) These days astronomers seem to avoid referring to brown dwarfs (which never quite make it to initiating fusion) as stars, but most things that used to be main-sequence stars seem to retain honorary star status... though I'm not so sure about black holes. I'm not sure how to be both precise and comprehensible here, given that the definition of a star, like the definition of a planet, is a somewhat arbitrary extension from pre-telescopic tradition. --Matt McIrvin 15:20, 11 Dec 2004 (UTC)

In the beginning of the stellar structure section it states that stars are in equilibrium. Stars are definetly NOT in equilibrium. Inside stars, matter is constantly moving and flowing in different ways. That statement is like saying the Earth's weather is in equilibrium. --Dan 19:02, 13 July 2006 (UTC)

I believe this is called "dynamic equilibrium". If a star is not a pulsating variable, for example, it's in equilibrium.
Umm... take a look at Dynamic equilibrium... a star is _not_ in dynamic equilibrium.

The majority of stars in our galaxy are red giants.—Preceding unsigned comment added by 75.9.36.189 (talk • contribs)

...red dwarfs actually. — RJH (talk) 23:41, 16 November 2006 (UTC)

I have a possible solution to the definition problem, in "The Angry Aztecs" by Terry Deary (part of Horrible Histories series) a star is defined:

'A Star is a large celestial body, containing gravitationally contained hot gases, emitting electromagnetic radiation - especially light - as a result of nuclear reactions inside the star.'

I thought that could be used as long as its quoted, any ideas?

Elwayfan01 03:22, 20 March 2007 (UTC)

The first paragraph already covers this, so I'm unclear why a quote is needed. The word "plasma" is more accurate than "hot gases". Also the statement "containing gravitationally contained" is somewhat ugly writing. Personally I'd prefer not to use this. Sorry. — RJH (talk) 14:56, 20 March 2007 (UTC)

The defining characteristics of a star include: - ball of plasma - very large and massive - nuclear fusion in core which counteracts the pull of gravity

These should all be included in the definition. Anisotropy 16:19, 30 July 2007 (UTC)

The first two are fine, and are covered by the lead. The third may be a problem. Not all stars perform nuclear fusion a the core; it can occur along a shell around a non-fusing core, or the star may have evolved to a post-fusion stage and some fusion can occur along the outer atmosphere. There is also the protostar that generates heat through gravitational energy, rather than fusion. So I'm not sure the statement that "A star shines because nuclear fusion in its core releases energy" is completely correct. It should probably say "A star can shine" or "A star normally shines" or "Many stars shine". — RJH (talk) 16:50, 30 July 2007 (UTC)
There are also questions as to whether any stars (even main sequence ones) have any nuclear fusion going on. The following web pages talk about this in more detail.

[1] (see the heading "AN ELECTRIC SUN" partway down the article) and [2] If you can, try and obtain the book The Electric Sky by Donald E. Scott (ISBN 0977285111). It also talks more about the facts involved. — Dmacgr 22 22:40, 30 November 2007 (UTC)

Is this spam? This isn't the right place to talk about radically different theories of physics. — RJH (talk) 00:06, 1 December 2007 (UTC)

Heterosexual POV

In the history of this article, there was something called a "Heterosexual POV". What does this mean?? 66.32.244.71 00:46, 19 Sep 2004 (UTC)

Some of the more common classifications are O,B,A,F,G,K,M, and can perhaps be more easily remembered using the mnemonic "Oh Be A Fine Girl, Kiss Me", invented by Annie Jump Cannon (1863-1941). (Variant; if you're a girl; change "girl" to "guy".)
became
Some of the more common classifications are O,B,A,F,G,K,M, and can perhaps be more easily remembered using the mnemonic "Oh Be A Fine Girl, Kiss Me", invented by Annie Jump Cannon (1863-1941). (Variant; change "girl" to "guy".) --Tothebarricades.tk 01:53, 19 Sep 2004 (UTC)

Numbers

This article uses billion, trillion, sextillion, etc. freely. It should be noted that this is using the short scale variant of these words, becuase they do have more than one meaning. Anyone mind if I add 109 to billion, etc, to clarify? Thanks, Ian Cairns 01:18, 24 Dec 2004 (UTC)

Possible error? In the Distributionsection , the article states: Astronomers estimate that there are at least 70 sextillion 7*10^22 stars. If you then click on the link for sextillion, it is defined as 10^21. It seems to me that these should match up (22 vs 21), or am I missing something? [[User:jftuga] 29, May 2007.

70 sextillion = 70 x 1021 = 7 x 1022. — RJH (talk) 20:25, 29 May 2007 (UTC)

space travel?

I think it would be more relevant to describe the length of time it would take to get to Proxima Centauri using the fastest means currently available to humans (i.e. rocket, space shuttle, whatever.) You wouldn't take the TGV to the moon, either. Being that I am neither an astronomer nor a physicist, I will leave this in someone else's capable hands to decide.

I totally agree. I looked at this, and my first thought was, who on earth (so to speak) would take a train to Proxima Centauri, let alone stop accelerating at a mere 500 kph? The use of slow static speed, enabling big numbers (and exclamation marks) for 'wow factor', seems unnecessary. But maybe I'm just on another obsessive encyclopedic-style crusade of mine. ;) -- Wisq 18:44, 2005 May 17 (UTC)
You're right. The Orion drive could get there in a lifetime. But it would take a spacecraft designed for allowing births and such since the time requirement would be beyond a woman's fertile years. BioTube 16:11, 17 July 2006 (UTC)

1

Distance and position of other stars?

I am trying to make a game with real star data. The problem is that I can't tell where the stars are! It would seem like a basic thing. Where are the stars? How can you find its position? How far is it to the star? I am using http://www.nstars.nau.edu/nau_nstars/multi_search_form.php as my source info. So what are the stars coordinates and how do you understand them? Are they based on the starting point as the Earth or the Sun or What? Are they polar coordinates? —Preceding unsigned comment added by 91.39.215.72 (talk) 08:54, 7 October 2007 (UTC)

My suggestion is to read the articles on Right Ascension and Declination. That will give you the position of a star on the celestial sphere, as seen from the Earth. The parallax can be used to find the distance. Personally I would use SIMBAD for your final data. — RJH (talk) 15:35, 7 October 2007 (UTC)

Thanks, I have found this and read it but I found one more problem. For example the star closeted to the Sun, NS 1439-6050, RA 217.43 Dec -62.68, Epoch 2000.19 Parsecs 1.3. To convert this to an X,Y,Z with the sun as center I used X=Cos(RA)*cos(Dec)*Par, Y=Sin(RA)*cos(Dec)*Par, Z=Sin(Dec)*Par. So this would be good but that each star has a different Epoch, that seems to be the position of the earth, using the earth as the base of reference. How does one use this Epoch? And does it need to be used? I will look into Simbad! Thanks. —Preceding unsigned comment added by 91.39.210.147 (talk) 09:56, 9 October 2007 (UTC)

  • You're close, but you also need to include a cos(δ) term in the x/y. See for example: User:RJHall/temp#Separation. I believe the epoch just reflects the change in stellar coordinates because of the Earth's precession and nutation. Personally I would just pick one and use that. We've been using ICRS 2000.0 — RJH (talk) 17:10, 9 October 2007 (UTC)

The data base I am using as a source has a different epoch for each star, thus I need to know how to correct for that or find a new data base with all the stars near Earth. —Preceding unsigned comment added by 91.39.210.147 (talk) 17:20, 9 October 2007 (UTC)

I updated the formula. Is it correct now? Yes, but those lists are to small, I was thinking more in the range of 10,000 stars but 2500 is ok. Thanks!! Douglas

  • Yes, if by Par you mean the inverse of the parallax in arcseconds. I'm not convinced that nStars is a complete database; I've seen several nearby stars which do not have entries. For 10k stars you would probably need something like the Hipparcos catalogue. Are you sure you want to be that ambitious? Perhaps you could try starting with the RECONS data? — RJH (talk) 18:57, 9 October 2007 (UTC)

Par is short for Parsecs as in the data base. But I am assuming that inverse of the parallax in arcseconds gives this? That is a great fact to have if it is true. The numbers of stars are not as important as being able to get all the facts into my program so that kids can start at Earth and with a "Warp" ship travel around and see what the neighborhood looks like. It is a tool to learn and explore. My parents grew up dreaming of going to the Moon. My kids will grow up dreaming of going to the stars. I want then to be able to play that dream with real stars in the computer. Perhaps I will make it a MMORPG too but that is the future. Again thanks for all your help! Perhaps at the end off this I can clean all this up into something helpful for others to read. Douglas.

  • Yes. Some sites list the parallax in milliarcseconds (mas), however, so you may have to divide by 1,000. You may also want to take note of stars with relatively large parallax errors; those values can change significantly with new measurements. Good luck with your project. — RJH (talk) 19:05, 10 October 2007 (UTC)

Alternating Colors?

I just noticed that stars (the bright ones, mostly) alternate colors. If my vision is correct, they flash a faint red, blue, and white. What causes this change in color?

This is an optical phenomenon due to atmospheric disturbances known as scintillation or (more commonly) twinkling. -- Xerxes 16:10, 3 November 2005 (UTC)

Dwarf or not dwarf

Sorry for the confusion, Main sequence has the necessary information. Kosebamse 21:01, 14 December 2005 (UTC)

Our sun a dwarf star ???

The article states:

"Small (dwarf) stars such as the sun generally have essentially featureless disks with only small starspots. Larger (giant) stars have much bigger, much more obvious starspots, and also exhibit strong stellar limb-darkening (the brightness decreases towards the edge of the stellar disk)."

See [[3]].

Either 'dwarf' or 'such as the Sun' should be omitted, but I can't decide which of the two. 84.160.245.26 09:05, 18 December 2005 (UTC)

Why? A reader unfamiliar with astronomy terminology might not realize that the Sun is a dwarf star. This is a fine place to introduce the two main sizes of star: dwarf and giant. -- Xerxes 15:47, 18 December 2005 (UTC)
Because following that kind of logic, a red giant would be a dwarf either. Our sun will become a red giant and after that a white dwarf. But it is not yet neither a giant nor a dwarf. Can you cite any serious sources that consider our sun to be a dwarf star (and not only small in mass) ? 84.160.231.213 21:12, 18 December 2005 (UTC)
There's more than one kind of dwarf. That's why there are other adjectives that come before it. White dwarf, brown dwarf, red dwarf, black dwarf, main sequence dwarf. The sun is a yellow main sequence dwarf (specifically type G2V). -- Xerxes 22:31, 18 December 2005 (UTC)
I see. So main sequence dwarfs are not a subset of main sequence stars but an alias name. Shouldn't this be explained a bit more in the article? I find it rather counterintuitive to think of a red giant as a dwarf although it has some logic that a giant by volume need not be a giant by mass. 84.160.231.213 08:46, 19 December 2005 (UTC)

Thank you for clarifying the article, ya loser, I could of done that myself. Just to check, I will try to say it again in my own words: our sun now is a yellow dwarf because of its luminosity (disregarding, for this very definition, volume and mass). It will become a red giant (gaining greatly in volume and luminosity but with constant mass) and then it will shrink in size and luminosity to become a white dwarf. Is this correct? 84.160.231.213 16:32, 19 December 2005 (UTC)

Yes, that sounds correct. Except that it's luminosity for a given temperature. It turns out what really counts is the radius of the star. Luminosity is basically a function of radius and temperature, so sorting by luminosity given a fixed temperature is equivalent to sorting by radius. -- Xerxes 19:29, 19 December 2005 (UTC)

"Dwarf" in this case is a legacy term in our star classification system, and is applied to stars of spectral type V (main sequence). This is true even for main sequence stars of much greater mass than the sun. There are also sub-dwarfs of spectral class VI--which are low metallicity. A white dwarf is a different animal, formed when a solar-mass star runs out of nuclear fuel, following the red giant phase. — RJH (talk) 21:37, 12 July 2006 (UTC)

The sun is apparently an average sized star. Look it up elsewhere people!

O2V

http://arxiv.org/abs/astro-ph/0503464 -- Xerxes 21:14, 21 December 2005 (UTC)


Temp/Bright

What kind of graph do you use oto show the temperature and brightness of stars. INFO NEEDED BADLY PLEASE HELP!!!!!!

I believe you are looking for Hertzsprung-Russell diagram. You might try Wikipedia:Reference desk for these kind of questions. DannyZ 00:58, 16 March 2006 (UTC)

Mention of individual astronomers

No offense to Dr. Figer, but does anyone else find it odd that the astronomers mentioned by name in this article are Hertzsprung, Russell, Eddington, Annie Jump Cannon, Flamsteed, Bayer, and Donald Figer? The first six are historical figures who made key contributions to stellar astronomy, but Figer is currently working. If Figer gets mentioned, shouldn't we have a paragraph about every moderately successful modern astronomer who works on stars? JustSayin 01:43, 21 March 2006 (UTC)

People will always plug their favorite people in Wiki articles; for every one you take out, you can expect two more the next week. At some point it becomes a question of who has the patience to remove all the extra junk while remaining sane. Feel free to help out. -- Xerxes 00:45, 22 March 2006 (UTC)

Stars - Birth of the Elements?

I've seen Carl Sagan's series: Cosmos, and need information about how the elements are formed. I can't quite remember how the elements are formed through the stars. a link, add-on to 'Stars' article, or explanation right here would be much appreciated.

A good starting place would be the Wikipedia articles on Stellar nucleosynthesis and Supernova nucleosynthesis. Both of these articles have links to other articles with more detailed information. --DannyZ 06:28, 5 April 2006 (UTC)

The universe is 13.7 billion years old?!

A direct quote as of the odd finding from the article:

"Small stars (called red dwarfs) burn their fuel very slowly and last tens to hundreds of billions of years. At the end of their lives, they simply become dimmer and dimmer, fading into black dwarfs. However, since the lifespan of such stars is greater than the current age of the universe (13.7 billion years), no black dwarfs exist yet."

Unless someone can prove me wrong... I'll look into it, but I do not think scientists know the age.

Reeves 00:14, 13 June 2006 (UTC)

Well, I just looked into it quickly on Wikipedia, even within it's own articles, the age is indefinite, even the article The Universe is uncertain. I think the wording should be changed.
Reeves 00:20, 13 June 2006 (UTC)
The age of the universe is known to better than 2%. -- Xerxes 03:15, 13 June 2006 (UTC)
Really... 2% accuracy, because I am in grade nine and I am on the subject right now, the given range is quite large 13.7 billion to 15 billion. >>>> I changed it, I swear, The Universe had a different number, new facts I guess, I'll continue to check it out.
Reeves 00:20, 14 June 2006 (UTC)
Sadly, most school systems can only afford to update their textbooks once a decade. WMAP has the most accurate determination of the universe's age; its results are about 3 years old now. Try googling "WMAP" or check out WMAP for more information. -- Xerxes 01:57, 14 June 2006 (UTC)
It took me long to reply, but I kinda gave up on the argument, I do now agree that the number is accurate to our understanding. Thank you though. By the way, schools out! -- Reeves 05:46, 25 June 2006 (UTC)
Yep, the number is correct. --Dan 18:55, 13 July 2006 (UTC)

Just don't forget that this age is relative to the Earth 71.77.58.103 13:16, 11 May 2007 (UTC)

This comment appears to be argument baiting from a creationist. — RJH (talk) 15:29, 11 May 2007 (UTC)

Naked-eye stars

Somebody wanted a reference about the number of stars visible to the naked eye. The Bright Star Catalogue lists all stars of magnitude 6.5 or higher, which is roughly equivalent to the number of stars that are visible to an unaided eye under ideal condition. (The eye would probably have to be pretty close to ideal as well, I would imagine.) Version 5 of that catalogue has 9110 objects, including stars.[4] :-) — RJH (talk) 16:32, 3 August 2006 (UTC)

Will all stars eventually be gone?

I have a question that has popped up in my mind a few minutes ago, and thus has been bothering me since. The question is, considering the sun has a few billion years of life left... as is the case for most stars, what happens when they are gone? Surely new stars don't get developed, right? So does this mean, technically, that there is an "end of the universe"? Spencer Thomas 16:48, 18 August 2006 (UTC)

Yes, it's expected that the stars will pretty much die out.[5] We're already past the peak star production rate. They estimate that 20% of the useful matter in the universe has already been used up as fuel.[6]
There's a write-up on the topic of the end of the universe at "ultimate fate of the universe". But if the big bang was born of the collision of two universe M-branes, I like to think that the whole shebang may get endlessly repeated. *shrug* — RJH (talk) 21:48, 18 August 2006 (UTC)
No all stars will not be gone as a matter of fact. As the elements become 'used up' as fuel, they will reach a heavy mass, and, under great gravity, and other conditions, begin to fission, creating smaller particles. The fact is, energy does not leave the universe as far as we know. Therefore, as more energy is released from these lighter elements, an instability will result and the larger elements will break down. This is also assuming that the universe crunches and then re-exapnds as another big bang. I cant say a second big bang because for all we know, there could have been a billion big bangs before us.

But it is very wrong to say that all stars will be gone. That is completely folly.


New stars certainly do form; they are forming right now. There may well be an end of the universe as it continues to expand, but not just because all the currently existing stars die out. thx1138 05:30, 19 November 2006 (UTC)
Yes new stars will form. But the rate of star formation is gradually decreasing, and over an excedingly long period of time most of the fuel used by stars will be consumed. See heat death of the universe, for example. — RJH (talk) 21:38, 24 November 2006 (UTC)
The universe gradually increases in entropy, so in an inconceivable amount of time the universe may well experience 'heat death' and stars will gradually wink out and die with none being formed, until there are none left. The universe will end up a silent, featureless sea of neutrinos for eternity. Maximum entropy. 81.151.208.35 20:53, 19 November 2006 (UTC)

Naming Convention

If you're interested please add your comment at Wikipedia_talk:Naming_conventions#Stars. Thanks AndrewRT - Talk 23:57, 20 August 2006 (UTC)

Size

I added a link to an article talking about a recent study which showed the smallest observed stars had 8.3% of the mass of the Sun, which is about 87 times the mass of Jupiter. The article mentions that they could have detected smaller stars, but since they couldn't see any it seems like 8.3% is the minimum size for a star. I did another edit to remove the seemingly outdated references to Doradus and the minimum estimation of 75 Jupiters. Then RJHall reverted all my edits.

I would appreciate it if someone could change the section to include the latest information. Here's the article which talks about this: http://news.bbc.co.uk/1/hi/sci/tech/5260008.stm —Preceding unsigned comment added by 24.6.48.36 (talk • contribs)

I apologize for the reverts. This article suffers from a lot of vandalism so it needs constant tending. There was an article in the New Scientist that clarified the topic slightly. The value of 87 times the mass of Jupiter is applicable to stars of very low metallicity. For stars with Sun-like metallicity, the cut-off is 75 Jupiter masses. So both values are correct; it's just that the BBC News reference didn't delve into the topic with sufficient detail. Anyway the section has been updated.
On the topic of the smallest star discovered, an ESO press release from 2005 says it's AB Dor C at 93 Jupiter masses. Another press release in NewScientist says it's OGLE-TR-122b at 96 Jupiter masses. They're pretty close. The reference is only a year old, so in what sense do you mean outdated? Thanks. — RJH (talk) 15:32, 24 August 2006 (UTC)



mass is a type of size (and there's a precedent, calling the population of a city its size) but Google does seem to show that the size of a star is its dimensions--diameter or volume; sites checked included Britannica, Hubblesite. Encyclopedia Britannica seems to favor diameter (or radius). Note Answers.com uses mass (but that might just be copied from Wikipedia) and KidsAstronomy.com uses magnitude!!! (Galileo used size to mean brightness, before we knew what stars were, and since brighter stars did appear bigger in his imperfect optics). So, we should be careful how we use the size vs. mass language in the article.--Todd 00:49, 24 August 2006 (UTC)

Picture Please! Take a look at this minute-long video comparing the sizes of planets and stars. Having a picture showing the scale of the differences would be very interesting.

Proxima Centauri's light...

Simba 16:28, 25 August 2006 (UTC): From the "Appearance and distribution" section, fifth paragraph, first sentence.
The nearest star to the Earth, apart from the Sun, is Proxima Centauri, which is 39.9 trillion (1012) kilometers, or 4.2 light years away (light from Proxima Centauri takes 4.2 years to reach Earth).
I'm no expert on such matters, but in another article on wikipedia (I thought it was light, but I just looked through and it's not there) I could've sworn I heard that light actually takes no time to get from where it is being emitted to where it is observed. In other words, light from Proxima Centauri doesn't take 4.2 years to reach Earth, it reaches Earth instantaneously. Am I mistaken?

Yes. Please see the speed of light article. — RJH (talk) 18:19, 25 August 2006 (UTC)

White to Brown to Black

This article says stars move from white dwarves to brown dwarves to black dwarves, yet I understand a brown dwarf to be formed from matter that conglomerates and never starts a sustained nuclear reaction. I've never heard of a white-to-brown-to-black sequence before.

I believe you may be correct. Perhaps the brown dwarf was intended in the sense of a body that does not have a fusion reaction the core? Or that it radiates primarily in the infrared? But the part stating "to brown dwarves" could likely be removed without harming the text. — RJH (talk) 18:36, 19 November 2006 (UTC)

The FAC

It was barely up there a week. How soon are these getting closed these days? Marskell 05:03, 7 September 2006 (UTC)

Yes it was pretty brief compared to some I've seen. Perhaps they're trying to expedite the process? But no matter. The article has had some more improvements and is undergoing another PR, so I'll just try again after a judicious delay. — RJH (talk) 15:44, 7 September 2006 (UTC)
I felt a little bad for you, actually. You were ready and willing to work on it. I'm curious to find out myself what the current closing standards are. I've got one up myself and don't want to see it arbitrarily cut off. Marskell 18:51, 7 September 2006 (UTC)
It might be because there was only one support amid all the comments. It's partially my fault - I objected but didn't get to strike out the addressed comments before it closed. I was surprised - RJHall seems so motivated, I thought the FAC would end up passing, even if it stayed for a while. I've been helping with the peer review, though, and I think it will pass its next FAC nomination when we reach that point. Pagrashtak 19:23, 7 September 2006 (UTC)
Actually I really appreciate all the work you've been willing to put into this article; it's in much better shape now. As Marskell mentioned, it was just a very fast FAC turn around. In the past there has been much more time to address FAC objections. — RJH (talk) 22:36, 7 September 2006 (UTC)

It's an FA! Woo-hoo! — RJH (talk) 16:53, 16 October 2006 (UTC)

Incomprehensible

This article is far to complex and incomprehensible. It is written at a level appropriate for a university science student, not for the general public. It does not contain basic information as to what a star is.

My main criticism is the opening paragraph. In this paragraph we should learn that stars are spherical and give off light. We should learn that stars are visible in the night sky and that one particular star is the source of most energy on Earth, including daylight. We should learn that stars are grouped into galaxies.

I'm sure one can see what I'm driving at. --58.109.24.120 02:26, 19 November 2006 (UTC)

Agreed. The style of the entire article is physics-talk, which is fine with me, except that the article should at least begin with the kind of basic definition that you describe. Spebudmak 04:34, 19 November 2006 (UTC)
Buhhh... well I guess we could always include a transwiki link to the wiktionary definition. — RJH (talk) 18:29, 19 November 2006 (UTC)

So everything should be dumbed down to the lowest common denominator. If we have to says stars are visible in the night sky we might as well assume that the user can't read either! Papermaker 00:27, 23 December 2006 (UTC)

Yes it's difficult to please everybody. When I compare this article to the FA'd photon, for example, the star article seems pretty tractible for a lay audience, at least to me. But perhaps some focus is needed on the simple english version to communicate similar information at a very basic level? — RJH (talk) 19:18, 23 December 2006 (UTC)

A lot of people think stars are SO nice!

I don't think this sentance should be at the end of the first paragraph. It doesn't fit the style of the rest of the article. When I attempted to edit the sentance out, I could not find it between the words "life span' and "Astronomers determine", and when I went to preview edit ( without changing anything) the sentance was gone. But when I clicked on article, to see the change there the sentance 'A lot of people think stars are SO nice!" was still there.

I am very confused. Hopefully someone with more wiki or html knowledge than myself could make sure the sentance " A lot of people think stars are SO nice!" was actually deleted, or could explain to me what is happening.

~~Jocelyn

Its gone and has been gone for minutes now. Your browser is showing you a previous revision. Gdo01 02:35, 19 November 2006 (UTC)
Clear your cache by pressing Ctrl-F5 (on a PC, I'm not sure about on a Mac). —Cuiviénen 05:12, 19 November 2006 (UTC)

Euro-centric

The "Observation history" section begins with the sentence "Stars have been important to every culture." It then proceeds to talk exclusively about observaions by European and American astronomers. If stars are important to other cultures then this should be elaborated upon. (Or, that sentence should be dropped.) Spebudmak 04:24, 19 November 2006 (UTC)

I disagree. The statement is true, but most of the section is focused on the modern scientific observation of stars using telescopes, rather than philosophical speculation based on naked observation. So, as much as you may not like it, a good deal of the key elements of the scientific understanding of stars comes from observations by European and American astronomers. If you have facts to the contrary, I'd be very interested in seeing them. Hopefully in the future the new discovers will be from a broader base, but in this case I don't see a useful alternative. Thanks. — RJH (talk) 17:55, 19 November 2006 (UTC)
The problem is that the introductory sentence has little in common with the rest of the section. If the section is indeed about "modern scientific observation of stars using telescopes" then of course it should talk about the people who did those observations, who were for the most part European and American. I am not contesting that. However, the first sentence gives one the impression that the section will talk about the impact that the night sky had upon various cultures, which it certainly does not. So, that sentence should either be scrapped, or elaborated upon, in my opinion. Spebudmak 21:22, 19 November 2006 (UTC)
Well we agree to disagree then. A re-write would be satisfactory, but a deletion of that paragraph is unacceptible, at least to me. There needs to be at least some comment in there about the early use of stars. Anyway I tried to expand on the text. — RJH (talk) 17:21, 9 December 2006 (UTC)

by who's definition?

after the "planet's definition changed and omg!" "controversy" on the media many people wonder who establish standards and definitions in astronomy, an "a star is .. according to" in the beginning of the article would be useful imo. --87.194.72.129 13:08, 19 November 2006 (UTC)

Star FA

Giving a star to an article about stars. How fitting. JIP | Talk 17:31, 19 November 2006 (UTC)

Opening section is getting trampled

The opening doesn't read like part of a high-quality, featured article tonight. Edits in recent days have muddied the intro. I can't figure out how to help clean up the section and maintain continuity, accessibility, and tone at the same time. --Dc3 05:56, 21 November 2006 (UTC)

I have made a contribution. I have reduced the process of a star to a single medium length sentence, leaving detail in the third paragraph. I have mentioned galaxies and the place of stars in the universe. The importance of stars has been taken from the 3rd paragraph and moved to the first. Elsewhere, I have removed repetition. --Dlatimer 06:24, 21 November 2006 (UTC)

I also agree that there is a problem with over-editing of this article, especially the opening section ... there has also been a rash of vandalism that seems to have gotten worse since star was featured on the front page – I would rather have this article temporarily locked than to need 20 of us babysitting it 24/7 ... as it is now it seems like an entirely new article (especially the opening section) every time I go to read it ... what can be done to help this? Ukt-zero 16:18, 22 November 2006 (UTC)

I've tried to help by adding still more editing--just for the first paragraph. Mostly I tried to broaden the intro and make it less technical, combining good ideas and nice phrases from Dlatimer and 58.109.24.120 (the one who called it Incomprehensible above). I don't think I got it quite right, yet, but I did my best for now, and I tried to be at least a little bold, before I got edit-fatigue. I think the vandalism has tapered off since the feature link expired--now you just have to deal with a couple of well-meaning neophytes like myself...Dc3 21:46, 22 November 2006 (UTC)

Yes the opening paragraph looks good, although I had to disagree with the assertion that life would not be possible without stars—we can't really be sure of that. It's always possible that other forms of life exist that we don't yet understand. Thanks. RJH (talk) 21:41, 24 November 2006 (UTC)

"luminous ball"... nice touch! --Dlatimer 02:08, 24 November 2006 (UTC)

Speculative nature of non-creationist star formation models

I believe it should be stated more prominently that non-creationist star models are very speculative. I cite the following in support: “We don’t understand how a single star forms, yet we want to understand how 10 billion stars form.” Carlos Frenk, as quoted by Robert Irion, “Surveys Scour the Cosmic Deep,” Science, Vol. 303, 19 March 2004, p. 1750. [7] Also, “In fact, given our current understanding of how stars form and the properties of the galactic center, it’s [stellar evolution near the galactic center is] not allowed to happen.” Andrea M. Gaze, as quoted by Ron Cowen, “Mystery in the Middle,” Science News, Vol. 163, 21 June 2003, p. 394. [8] In addition, “For example, no one can explain how the stars—which are 15 times heftier than our sun—got there [near the center of our galaxy]. According to most astronomical models, they are too big to have formed in the chaos of the galactic center but appear to be too young to have moved there from farther out.” Robert Irion, “The Milky Way’s Dark, Starving Pit,” (Science, Vol. 300, 30 May 2003, p. 1356 ). [9] Lastly, “We cannot even show convincingly how galaxies, stars, planets, and life arose in the present universe.” Michael Rowan-Robinson, “Review of the Accidental Universe,” New Scientist, Vol. 97, 20 January 1983, p. 186. [10] 136.183.154.15 03:53, 29 November 2006 (UTC)

Creationist star-formation models are, of course, false. This is banned user "kdbuffalo" attempting to evade his ban. This address is likely to be blocked, but he may use others. --Robert Stevens 09:49, 29 November 2006 (UTC)
I think I would say, rather, that they are non-scientific. It's always possible to concoct an extreme scenario under which a creationist viewpoint is "correct". But no scientific test has yet been found that can validate it. Otherwise, yes, I completely agree. The poster is attempting to turn scientific impartiality into evidence of falsehood. — RJH (talk) 16:17, 29 November 2006 (UTC)

Astrology removal

I've been browsing some of the wiki pages on individual stars. Some pages discuss the science of the star and nothing else, whereas other wiki pages discuss the science and the astrology of the star. Consistency is needed. I nominate removing all traces of astrology from these articles. If some astrology people want to maintain it, then it should be moved to a separate article. E.g., there should be a page about Aldebaran and another page about Aldebaran in astrology. I'm sorry I had to put this idea on the star talk page, but I didn't exactly want to put this idea on each stars' discussion page ;-) .--Just James 23:56, 6 December 2006 (UTC)

I disagree. Astrology has historical relevance and is closely associated with early astronomy. As long as the statements are factual and do not make non-scientific assertions I don't see a problem. — RJH (talk) 17:19, 9 December 2006 (UTC)
Very well, but I'm arguing for some consistency. Either each individual star article should discuss whatever astrology stuff about themselves or there should be separate pages for the stars that do have astrology stuff about themselves. It's like what has already been done to stars appearing in fiction. Separate pages have been made for that topic because not every star appears in a fictional text. So again I think that there should be, for example, pages for: Aldebaran, Aldebaran in fiction and Aldebaran in astrology. There is already a separate page for Aldebaran in fiction. The same should be done for astrology because not every star article has an astrology section (astrology may not have been disucssed for every star, particularly the minor stars).--Just James 01:50, 11 December 2006 (UTC)
In cases where the fiction regarding an astronomical object has been moved to a separate page, usually there remains a reference to that content on the object page. (E.g. Andromeda_galaxy#Andromeda_Galaxy_in_fiction) This is if for no other reason than to direct people interested in that aspect of the topic to the proper page for editing. (Otherwise I tend to find that the information slowly gets added back in.)
For astrology, however, in some cases the information may be relevant to the object's etymology. In that case I think it's consistent with retention. But I certainly have no issue with a separate page providing expanded content regarding the astrological particulars. I'd just like to keep the astrology content that is specific to etymology, and the cultural and historical references. Thank you. — RJH (talk) 16:43, 11 December 2006 (UTC)

Life without stars

Is is theoretically possible? Could a lifeform of any kind survive in a universe without stars? Would they ultimately survive long enough to create their own sources of power? - 86.151.100.68 16:28, 28 January 2007 (UTC)

No. Life without medium-size atoms is inconceivable.--Dlatimer 14:40, 3 February 2007 (UTC)
Impossible is too strong a word--Robert Forward's Cheela have no atoms, and I do not think it to be too much a stretch. I suggest reading "What does a Martian Look Like?" by Martin Gardner and Jack Cohen.--Todd 17:41, 3 February 2007 (UTC)

First Paragraph

In the first paragraph it says that "A star is an extremely large ball of luminous ball of plasma".... large ball of luminous ball? Is that right? I mean, it sounds weird, and it doesn't make a lot of sense. Can someone fix this? —The preceding unsigned comment was added by 69.79.66.172 (talk) 15:28, 18 February 2007 (UTC).

Requesting semi-protect

I just counted, and in the last 50 edits over the past six days there have been 21 reverts. I propose that this page becomes semi-protected for the time being.--十八 08:23, 12 March 2007 (UTC)

I'm all for it—I tried before to get semi-protection, but it was only done for a brief interval. — RJH (talk) 19:07, 12 March 2007 (UTC)
I have requested this page to be semi-protected now. I don't think it'll be declined.--十八 00:41, 14 March 2007 (UTC)
This page is now semi-protected.--十八 09:18, 14 March 2007 (UTC)
Good. Thank you. — RJH (talk) 16:42, 14 March 2007 (UTC)

Bet you find this Interesting?

I had a thought the other day. And tried to find this answer to this on Wikipedia and other sources. But as a complete layman became very confused, parsecs/light years ect. This is my thought, we (the human race) have been sending out RF signals of a reasonable strength since 1922, please correct me on this if I have this wrong. Based on this knowledge, I wondered how far and how many star like suns (G class stars) have these RF signals reached by this year, 2007 ? You know where I'm going with this thought, and yes maybe life is not restricted to G class stars, or maybe it is, or maybe only to G2V, and we all known G2V's are capable! Then there's the age of these stars, and then the metallic make up as well. I wish someone with the right knowledge would draw up a list of theses stars. And using the above knowledge. We could then break the list up into the most lightly to the most unlikely places that intelligent life may exist. And that have also received RF signals from us. I believe this list would be helpful to SETI, to reduce their listing down to size, so they can focus on a more broader range of RF signals. As I also believe the RF's they are searching are far too narrow, and I feel a lot of time and money is going to waist at SETI. If anyone can help me with this please do, maybe I've got this wrong as I'm just a layman. But in any case, post me something, its bugging me! —The preceding unsigned comment was added by 86.10.204.128 (talk) 23:51, 20 March 2007 (UTC).

see here: List of nearest stars, this shows all stars within 5 parsecs (16.308 light-years). Patrick1982 16:21, 21 March 2007 (UTC)
Early radio signals were weak (drawing only a few watts) and may have been drowned out by the solar radiation. However modern radar can operate at tens to hundreds of megawatt, so they may pick up our defense systems radars. The number of class-G stars reached by our transmitters increases roughly as the cube of the radius (=time), at least until it reaches the edges of the galactic disk at which point it increases more as the square of the radius. But this assumes that anybody is even listening. We've only been doing so for about 0.000 001% of the age of the Sun. — RJH (talk) 14:54, 22 March 2007 (UTC)

84.20.65.162 10:12, 8 April 2007 (UTC)[[Image:Example.jpg]]

Edit requests

I suggest a slight change to the latest edit by 02:36, 8 April 2007 by Crescentnebula. In the sentence "Because of the relatively vast distances between stars in the outer regions of the galaxy...", replace "the outer regions" by "most regions". Timb66 10:20, 8 April 2007 (UTC)

I would disagree with that. That sentence sets up the context for the following sentence that then talks about where stars are closer together, astrologically speaking of course. Also, "most" is a weasle word, and we're trying to be specific as possible, espeically for an FA. I did however change "because of" to "due to" since I believe it is bad grammar to start sentences with because.--十八 10:43, 8 April 2007 (UTC)
I agree that this sentence links to the following one, but I still think "outer regions" is misleading. To me it implies outskirts, but not necessarily the majority. It is certainly true that the stellar density in the vast majority of the galaxy (both disk and bulge) is too low for stellar collisions to occur with significant frequency. I don't think "most" is a weasel word in this context. It simply means "majority", something that is not implicit in "outer regions". In fact, "outer regions" is actually wrong given that many globular clusters are in the outer regions of the Galaxy. (I notice the page is no longer protected, but I thought I would discuss here before modifying the page) Timb66 01:57, 9 April 2007 (UTC)
I agree with you Timb66. In fact I'd go so far as to say "outside the core region" of the galaxy. — RJH (talk) 16:34, 9 April 2007 (UTC)

Variable stars

I have removed the statement that "The variability is caused by the stellar aging process, which produces changes to the outer envelope" because it misleading as it stands. The pulsations are caused by a feedback process that works like a heat engine, which is quite well explained in the page on asteroseismology. Some stars go through stages during their travel in the HR diagram in which they are unstable to these pulsations, and temporarily become pulsating variable stars. I think the page on variable stars needs to be updated to describe this more fully. cheers, Timb66 22:27, 15 April 2007 (UTC)

I was going by the reference, which stated that, "types of pulsating variables may be distinguished by the pulsation period, the mass and evolutionary status of the star, and the characteristics of their pulsations." Some mention of evolution seems appropriate. — RJH (talk) 15:56, 16 April 2007 (UTC)

Hi RJHall. Ok, thanks, that looks good now. I think the info on variable stars could be expanded in Wikipedia. I was about to say that there is not even any reference to the Instability strip, but then I found it! Howevere, it is not linked from the page on variable stars at the moment. What is really needed is a separate page on stellar pulsations. Please feel free to start one if you have the time! It is my area of expertise and I am happy to help. Timb66 21:46, 16 April 2007 (UTC)

Hi Timb66: I added a request for a "Stellar pulsations" page on Wikipedia:Requested articles/Natural sciences#Astronomy_and_cosmology. Thank you. — RJH (talk) 22:26, 16 April 2007 (UTC)

Flare stars probably count as intrinsic variables and should be added there, though they don't fit into the categories of intrinsic variables mentioned here. Also, most flare stars are also spotted and show that form of extrinsic variability too. BSVulturis (talk) 22:39, 7 February 2008 (UTC)

Yes they are, but covering every possible variable star would be prohibitive on a summary-style page. The variable star has a section on the topic (although that page needs lots of work).—RJH (talk) 19:48, 8 February 2008 (UTC)

New Picture

I would normally just add this myself, but we allready have a picture like this. So vote if wr should include this picture in the article: -- Penubag  01:25, 2 May 2007 (UTC) File:H-R diagram.gif

Vote here

  • Minor Include- shows where most of the stars are in our universe, but the one we all ready have is fine. But I personally like this one better and it's easier to read if inlarged.  Penubag  02:25, 3 May 2007 (UTC)
  • The new one is better in that it has more axis labels (temperature, etc.) and gives a better idea of the relative frequencies of different types. The main thing I dont like are the lines labelled luminosity classes (I, II, II, etc). They are very arbitrary and not used in practice. But overall, I vote for the new one. Timb66 05:24, 2 May 2007 (UTC)
    • Hey, I guess you can't go against a collage professor =-) BTW, I can edit the picture to fix some minor changes and label where the sun is-- Penubag  06:17, 2 May 2007 (UTC)

Yes, that would be good. Is it possible to delete the upper five lines (but leave the labels)? The lines for Main Sequence and White dwarfs are ok (these are real sequences), but the other lines are not really sensible. Timb66 12:24, 2 May 2007 (UTC)

  • Strong Object — Well obviously I'm going to object since I choose not to include that image in favor of a H-R diagram with considerably less detail. But that is my reason: this version has far too much detail for this page, when all that is needed is a summary. In order to be fully visible it will need to be expanded to enormous dimensions, making it a hideous and non-aesthetic insertion. It's a fine diagram, but I think it definitely belongs on the Hertzsprung-Russell diagram page where it can be described in more detail. — RJH (talk) 16:20, 2 May 2007 (UTC)
  • Comment - The diagram looks great. I did not understand Timb66's complaint about the luminosity classes, but maybe that's because I work in extragalactic astronomy. (I usually am only really interested in the luminosity classes when trying to identify stars for use as spectroscopic standards, in which case I use V stars). The one problem that I see with the diagram is that it needs to be fully magnified to view all of the detail. If it is made too small, it will be too difficult to read the text. Is it possible to create a smaller version without changing the pixel size of the font or to create a version with thicker font? Dr. Submillimeter 16:55, 2 May 2007 (UTC)


  • Object - it's too large. I love the look of it, but would like one about 60-70% the size. It cannot be shrinked by using [[Image:H-R diagram.gif|500px]], because it doesn't look well:
File:H-R diagram.gif
It must be regenerated from code. Said: Rursus 18:40, 2 May 2007 (UTC)

Actually my personal preference would be for it to display well at the current HR image size of 320px:

File:H-R diagram.gif
Reduced to 320px

Viewers can find large images objectionable. — RJH (talk) 19:07, 2 May 2007 (UTC)

  • ok, I am persuaded by the above arguments: it is too complicated for this page. I change my vote to keep the existing diagram. Timb66 23:34, 2 May 2007 (UTC)

The Decision is: No include but I am working on a picture that we may be able to use  Penubag  02:25, 3 May 2007 (UTC)

Upgraded HR

File:H-R diagram -edited-.gif
I changed the font size and added additional information to the original pic. -- Penubag  03:23, 3 May 2007 (UTC)

File:H-R diagram.gif
(ORIGINAL PIC)Reduced to 350px
File:H-R diagram -edited-.gif
(NEW PIC)Reduced to 350px and IMO, it looks a great deal better, but vote here if we should include this in the article.


Update to main star page??
Vote here: Minor Support Still not too sure -- Penubag  03:21, 3 May 2007 (UTC)











































  • I suggest moving this discussion to Talk:Hertzsprung-Russell diagram, where the earlier version of this figure currently resides. I like the revised figure, ut I still think it is too complicated for this page. Note that the label should be "Spectral type", not "Spectral class". Also note that I have just put the correct coordinates of the Sun in the caption on the Hertzsprung-Russell diagram page. Timb66 04:51, 3 May 2007 (UTC)
    • We can move this conversation if you want. Also if you strongly think I should change "Spectral type" to "Spectral class" tell me, and ill change it, but I think it is okay for now as is. Another note, not to be bias or anything, but I think my picture would benifit the Star page more than the simple one. The simple one it too confusing, not enough labels, and really just a bunch of colored dots and one labeled as our sun. Okay, Im exaturating too much but you get the point. Personally a labled, detailed diagram is better than one that isn't and if you think about it, the new diagram isn't really any more complex than the other one, except for more labes, axies, and stars (which are all vital IMO). Also just as a side note, I'm not defending my picture just becuase I improved it, I really think that it would serve better on the front page. -- Penubag  05:18, 3 May 2007 (UTC)
  • Comment Since this discussion affects this page I'd rather it occur here. The revised small image looks fine with the exception of the anglicized word "colour", the redundant "Luminosity" entry, and the dark-blue coloration of "Spectral Class" (which is difficult to read against a black background). Also does your graphics editor support anti-aliases fonts? The edges of the text looks jagged. — RJH (talk) 16:07, 3 May 2007 (UTC)
    • Okay, so I should revise the picture by changing: Spectral class-->spectral type , delete second Luminosity entery, and possibly the dark blue font color at the top. Please add to this list for more. But I don't think I would want to change the dark blue color at the top. I was also thinking the same thing you were, that it might be hard to read, but after thinking for some time, I decided dark blue was best (Green was actually first choice, but green doesn't seem to work in my editor) dak blue because any other color would confuse viewers. If it was goning to use white text, than you wouldn't see some of the text under it, red blends in with the "K" and "M", yellow with the "F" and "G". So, no other colors would suit that position besides Dark Blue (light blue blends with "O" "B" "A"), and Dark Green (which is even worse). My graphics editor doesn't support anti-aliases fonts, sorry. Also what Timb66 was saying was the top 5 purple lines, which I cannot take out without spending atleast 30 minutes on it. So if you strongly suggest taking the purple lines out, I will, besides, I think the purple lines are informative. So add to my list up there and I will fix the picture.-- Penubag  22:08, 3 May 2007 (UTC)
      1. Not to seems rude, but the dark blue text is nearly unreadable; I think that getting rid of that hue (against the black background) is an absolute must. I can't imagine what somebody who is color-blind might see. (C.f. Wikipedia:Accessibility#Color.) What is wrong with just using white? Also your text is too clumped together at the top. RJH (talk)
      2. If you don't have anti-aliasing, perhaps you might consider using a better-quality graphics editor? Anti-aliasing is readily available. Or let somebody with the right tools do it. RJH (talk)
      3. The purple hue look fine to me. It has a nice, high lightness. The lines do suffer from the jaggies, though, due to the lack of anti-aliasing. No offense, but to my somewhat artistically-inclined eyes that seems a little unpolished. — RJH (talk)
          • Okay so I will change the darkblue text to White. I was able to read it fine, but I forgot about colorblindess or sensitive vision. I was just worried that white would blend into the other letters, but maybe not (I still wish light green were avalible :-p). I don't see where the text is clumped though, perhaps you could clarify. My graphics editor is really primative and I don't know anyone that has a good one. Maybe we should just keep the old image? What do you say? Even though I think this one is a great deal better, maybe it has too many problems. BTW, no offense taken,RJHall. =-). Also as another note, I had an astronomy professor who's last name was Hall. His full name was Prof.Jandorf Hall-- Penubag  22:16, 4 May 2007 (UTC)
            • If white blends too much, you could always use a light gray. What I meant by the stacked text was the spectral classes section along the top. The dark blue text is touching the individual spectral classes, rather than having a gap. I think if you just expanded the image three pixels along the top and then moved the "Spectral class" line up it would be an improvement. I can make out the dark blue text but I have to squint a little. But I have had friends, and one color-blind physics professor, who wouldn't be able to see it at all. Also some hues can vary a little by monitor type and settings, so maybe the dark blue shows up better on your display? Thanks. — RJH (talk) 18:46, 5 May 2007 (UTC)


So, yes/no include in article? -- Penubag  00:46, 7 May 2007 (UTC)


Looks nice. I have no strong opinion on whether to put it on this page, although I am inclined to say no, but it should definitely go on the HR page. Can you remove "(Color)" from the top, please? Spectral type is certainly not a measure of colour, it measures the presence (and strength) of various features in the spectrum. Also, the arrow to the Sun is not pointing to the correct place. The correct coordinates of the Sun in the caption to this figure on the Hertzsprung-Russell diagram page. And rather than an arrow (without an arrow head), perhaps put a spot there and write "Sun" next to it? Timb66 01:47, 7 May 2007 (UTC)

Final


So how 'bout now? =-) -- Penubag  05:08, 7 May 2007 (UTC)

  • Okay I'll change the front page and if there is no protest at all, then I will keep it. However if any one person protests, I will revert back to:
    Old Version



























I'm not intending to compete with the above image, this is about star navigation, not about a physically correct HR-diagram from true data. My HR-diagram looks like this:

It's used for jumping from one star category to another, but:

Have I got everything correct?

Grateful for comments and corrections. Said: Rursus 18:47, 2 May 2007 (UTC)

Maybe this is an old-fashioned version of the HR diagram. Astronomers typically do not divide stars into "supergiants", "bright giants", "giants" and "subgiants" as is shown above. Instead, astronomers would divide stars into classes such as horizontal branch stars and asymptotic giant branch stars, which are classifications based on the phenomenology of the stars and not just the stars' luminosities. It would also be very useful to have links to the spectral types, which is as important as the luminosity classes. Dr. Submillimeter 21:58, 2 May 2007 (UTC)

That is not completely correct. We still subdivide into these classes, but not using the lines shown here. For example, a subgiant is a star that has "recently" left the main sequence and is burning hydrogen in a shell around the helium core. My objection to the lines for classes IV, III, II and I on the diagrams is that they have no physical or observational basis, and are not in use. The line for the main sequence (V) is ok because it is a real sequence: it is the locus of stars that are burning hydrogen in the core. You could also describe it as an isochrone of stars with zero (or low) age. (Oh dear, look what happens when you follow the isochrone link!) The line for white dwarfs is also ok, since it shows an evolutionary sequence (white dwarfs go down this sequence as they cool). I suppose the other lines also show the locations of the subgiant, giants and supergiants. But they just look so weird to me! I have never seen a diagram based on actual observations or calculations that shows lines like these, they only appear (admittedly with high frequency) in popular books. Hmmm, I don't know. I never thought much about it before. There are certainly more pressing issues. For example, have a look at the page on giant stars!

By the way, the colours on this latest figure are strange. There is no such things as a green or purple star! Timb66 00:00, 3 May 2007 (UTC)

Was long time ago this was decided upon, but factually: WC Wolf-Rayets are varying nuances of purple, from blue-purple to red-purple, due to two strong emissions, one in blue and one in red. About green stars: I think there are none, but who knows? Theoretically, if one star exhibit a very strong emission in green, the star could be green. Imagine a fast rotating star with a hot ring, and the ring happen to have a temperature such that an emission of Fe or Mg around E or b lines dominate the spectrum... Said: Rursus ☻ 23:40, 3 November 2007 (UTC)

New discovery upsets the 'single period for star birth' theory?

ScienceDaily posted an article today about a new discovery that upsets the 'single period for star birth' theory. I don't know much about stars, so maybe one of you could look at the article and decide whether it's worth including it in Wikipedia. Here's the article. Dionyseus 20:58, 2 May 2007 (UTC)

I believe it had to do specifically with globular clusters. I've added in a reference and some text to that article. Thanks. — RJH (talk) 22:25, 2 May 2007 (UTC)

Big Bang

Note that some lithium and (I think) also beryllium were created in the Big Bang. Therefore, the opening paragraph needs some editing. Timb66 10:04, 6 May 2007 (UTC)

Yup, a massive one atom in ten trillion. ;-) — RJH (talk) 20:58, 10 May 2007 (UTC)


Sun closest?

The sun is NOT the closest star to the Earth it's the moon. A moon is a type of star. Aishe zq 23:48, 11 June 2007 (UTC)

Stars shine by their own light. Moon isn't a star because it reflect light from the Sun. --Banus 20:17, 11 June 2007 (UTC)
I know but ... some stars reflect light and use that light while others make their own light. Look up your info theirs new information. people have learned more about stars and the moon IS as star. Look up your info like i said before. Oh ya remember to use only web sites that have new info. After all the way your talking you'd believe that pluto was a planet. Aishe zq 23:48, 11 June 2007 (UTC)
Aishe zq is right! the moon IS a star and its closer to earth than the sun so it's the closest star.Smartestgurl 14:12, 12 June 2007 (UTC)
Hasn't anybody told you it's not safe to drink and drive on the internet? — RJH (talk) 15:21, 12 June 2007 (UTC)
Hasn't anyone told you not to talk about things you don't know about? Aishe zq 20:44, 15 June 2007 (UTC)

Not to polemize, but stars by definition need to "burn" or have "burned" Hydrogen in their core. Brown dwarves may be an exception but I think their nature is still to be defined. The moon does not fall into that classification. Also the moon formed in a completeley different way (probably accreting smaller rocks or separated from Earth) than a star does (basically a big cloud of gas collapses). So no, the Moon is not a star. http://www.nmm.ac.uk/server/show/conWebDoc.299 http://imagine.gsfc.nasa.gov/docs/science/know_l2/stars.html

They got it backwards, every child knows that the Sun is a Moon! Because it revolves around earth, and earth is a planet! Said: Rursus ☻ 23:48, 3 November 2007 (UTC)

Magnetic field

A sub-section on Magnetic field needs to be added to the Characteristics section. The Wikipedia:WikiProject Missing encyclopedic articles/Hot/S4 has a request for Stellar magnetic field, so the subject may need a separate article as well. (Also listed are Stellar rotation and Stellar temperature.) — RJH (talk) 19:02, 19 June 2007 (UTC)

Agreed. This is a fairly big subject. The articles on the Sun and sunspots are relevant to this. Also dynamo theory and surely lots more. Timb66 00:07, 20 June 2007 (UTC)

Okay I put together a start-class article on the topic. But it can obviously be expanded considerably. Thanks. — RJH (talk) 19:14, 21 June 2007 (UTC)

Stars in other galaxies

The article states that individual stars have only been studies in our galaxy. Surely this is wrong, and stars such as cepheids have been observed in (for example) Large Magellanic Cloud and the Andromeda Galaxy. GB 12:00, 27 July 2007 (UTC)

yes, it is wrong. I have removed that paragraph. Timb66 05:38, 29 July 2007 (UTC)

Thanks. Yes, the standard candle article includes several examples. — RJH (talk) 16:33, 29 July 2007 (UTC)
The stars are in the local supercluster; there is only one exception to the known star cluster observed at distance greater than 100 million light years. While faint individual stars are observed in nearby galaxies, the vast majority of known stars are from Milky Way. The question how far can we see stars is a natural one and the article should discuss it. Terse 01:48, 2 August 2007 (UTC)
Perhaps, but it's as much an issue regarding the instrument as it is the star. The section on magnitude already has some discussion concerning observation of distant stars. Perhaps a sentence in there would satisfy the topic? — RJH (talk) 16:20, 2 August 2007 (UTC)

"With the exception of supernovae, individual stars are for the most part observed only in our Galaxy."

I'm not sure this opinion is correct. There are 1010 stars in the Large Magellanic Cloud, for example, and many individual stars have been observed.[11][12][13] By contrast it can be difficult to observe stars in the Milky Way due to intervening gas and dust. — RJH (talk) 19:02, 2 August 2007 (UTC)
true, but a majority of stars observed are in our Galaxy. However, it is a bit of a vague statement and I do not know any statistics. Nevertheless, the question how far stars can and are being observed is natural one and people reading the article might be interested in this. Terse
Sorry to be tedious here, but you make your statement as if you knew it to be fact. If so then where does this fact come from? If we can observe individual stars in the Andromeda Galaxy, but a substantial portion of the Milky Way is obscured, is this in fact true? It just sounds like a personal opinion. — RJH (talk) 21:15, 4 August 2007 (UTC)
I took the liberty of making a few small modifications to the text, with references. Thanks. — RJH (talk) 17:47, 5 August 2007 (UTC)

Are all stars in galaxies or are there some 'lone stars' in intergalatic space? 81.97.30.187 10:00, 11 August 2007 (UTC)

I don't think that there's any way that 'lone stars' could be definitively ruled out; after all, it's a big universe. Perhaps if there were small clumps of gas and dusts, singular stellar clusters could be formed somewhere in intergalactic space? Also there are very likely stars that were formed in a galaxy and then were ejected out of the galactic halo because of galactic interaction. — RJH (talk) 15:54, 11 August 2007 (UTC)
Thank you, is there any evidence of such stars? 81.97.30.187 16:26, 11 August 2007 (UTC)
Yes it looks like there are: http://hubblesite.org/newscenter/archive/releases/1997/02/ — RJH (talk) 20:01, 11 August 2007 (UTC)

There are quite a few papers on hypervelocity stars (check the ADS). These stars are in our galaxy but have velocities so high that they will eventually escape. Finding such a runaway once it has left our galaxy would be hard because it would be very far away and faint. The current theory seems to be that they were ejected from the galactic centre when a binary passed close to the central massive black hole, and one of the stars received a huge gravitational kick. I think that a three-body interaction is needed to produce such a large velocity, and that at least one of the three has to be very massive. Timb66 22:46, 11 August 2007 (UTC)

This paper presents a possible third mechanism in the form of star formation out of gas that was previously ejected from a galaxy. They've also found extra-galactic planetary nebulae, and, for Virgo at least, 15% of the galaxy's mass has been ejected. Huh, learn something new every day. There may even be enough material out there for an article on intergalactic stars... — RJH (talk) 16:10, 12 August 2007 (UTC)

Burn duration

The table for O-class main sequence star burn duration has typo in S/Si entry? In revisions before 5 June 2007 the entry is given in days, and in later revisions the entry is given in years but the number is unchanged. JTMnen 10:29, 22 August 2007 (UTC)

Good catch! I checked the reference and the 11.5 is in days, so I modified it to fractional years for consistency. Thank you. — RJH (talk) 14:55, 22 August 2007 (UTC)

lala —Preceding unsigned comment added by 67.185.11.36 (talk) 04:25, 15 October 2007 (UTC)

Supernova

Only the largest stars can have a supernova. Our Sun is actually not large enough to. It will simply expand until its gases float off into space.--4.249.210.74 22:05, 11 November 2007 (UTC)

The 'Collapse' section covers core-collapse supernovae. Type Ia supernovae are caused by accreting white dwarfs in a binary system, or by a (rare) collision between two white dwarfs. — RJH (talk) 16:53, 12 November 2007 (UTC)

Field stars

These are nowhere mention, but they outnumber stars in globular clusters by several times as I understand. --Mrg3105 11:59, 13 November 2007 (UTC)

I assume you mean this, a star that falls along the line of sight to the cluster? I'm curious to know where you heard that they outnumber the stars in the cluster? It should depend on where the cluster is located in relation to our galaxy. — RJH (talk) 17:15, 27 November 2007 (UTC)

Choppy paragraphing --> FAR?

The article needs to be smoothed out by integrating some of the subby paragraphs into their neighbours. I think this needs to go to WP:FAR for the purpose, unless anyone's willing to do it in the meantime (?) Tony (talk) 08:28, 26 November 2007 (UTC)

I can take a crack at it. Most of this problem has happened because of innumerable small revisions since the FA. — RJH (talk) 18:23, 26 November 2007 (UTC)
Ah, thanks; that would be excellent. Tony (talk) 03:43, 27 November 2007 (UTC)
I've done some updates. Are there any other parts of the content where you have a concern. — RJH (talk) 18:19, 30 November 2007 (UTC)

second sentence

Because it's exposed right at the top, I'll say that this is an awkward joining of ideas into one sentence: "Stars dominate the visible universe and they group together to form galaxies." Don't know how to fix. Maybe treat below the first para as a stand-alone para that deals with the conglomeration of stars into galaxies: a little more info could be given here, including how many galaxies, and thus how many stars, the universe is estimated to contain. Good for the non-experts like me. Tony (talk) 08:51, 28 November 2007 (UTC)

I was not happy when that sentence was added and I wouldn't miss it if it were removed. I reversed the order because the sentence had been modified into an ambiguous form. It's also not quite accurate, in that galaxies form from conglomerations of dus, gas and dark matter. Stars are just a side effect, and they form a minority of the total galactic mass.
The lead is supposed to be a consise summary of the article. The discussion of the number of stars in the heavens is just a small part of the total article, so I think the summary should be even more brief. Perhaps it could be included in the final paragraph? — RJH (talk) 15:48, 28 November 2007 (UTC)

I agree and suggest the second sentence be deleted from the lead. Timb66 (talk) 20:39, 28 November 2007 (UTC)

As there was no disagreement after a week, I removed the second sentence. — RJH (talk) 23:23, 6 December 2007 (UTC)

Etymology

The Etymology of the word Star on this page is wrong. It in fact disagrees with the reference it cites! (Online Etymology Dictionary).
The word in devanagri is misspelt as सितारा (satiara), which should be िसतारा (sitara) instead. Also, this word is not Sanskrit as stated - it is of Farsi (Persian) origin1, and now in common use in Hindi. The corresponding Sanskrit word is तारा1 (tara), also in common use. The Online Etymology Dictionary actually agrees with Oxford Concise Dictionary and Chambers English Dictionary, giving Old English 'steorra', Greek 'aster', Latin 'stella', German 'stern' (amongst others), but not the Sanskrit word.
I consider it unlikely that the Farsi word (Farsi being Middle/New Persian ?) is the origin. Unless somebody has profound knowledge on this matter, sticking to what Oxford, Chambers and Online Etymology Dictionary concur on would be wiser.
However, the article might be better-off without an etymology, for none of these words give any historical background or any other kind of insight about stars. You might want to know the etymology of "Fata morgana" to see how the word came about, or appreciate knowing that "disaster" refers to being under a bad star, but a star is only a star in any language in any era, and the origin tells nothing more.
I shall wait for responses here for some time before editing the main-page.

1 "Brihat Hindi Kosh" (by Gyanmandal Ltd.), a reliable Indian dictionary.

--Ankurtg (talk) 20:08, 6 December 2007 (UTC)

I find it hard to believe that the word spread between any of these languages. Surely it has been in use for many many thousands of years, and all the similar sounding terms came from an ancient Proto-Indo-European language. Graeme Bartlett (talk) 21:08, 6 December 2007 (UTC)
It's won't break my heart to see the etymology removed. Although some will disagree, I think it belongs in the wiktionary anyway. The etymology/pronunciation in various articles always seem to go through a lot of excessive churn, as if people can't agree or get it quite right. — RJH (talk) 23:21, 6 December 2007 (UTC)
I have removed the Etymology. To reiterate, the entity "star" would have been known to any ancient civilization and the origin of the name reveals nothing of interest. Also, the existing information is wrong. (I now suspect that the error in the devanagari script (सितारा / िसतारा) is due to a discrepancy between web-browsers. The original word appears right on IE 7.0, but wrong on Mozilla Firefox 2.0). Either way, the fact is incorrect.--Ankurtg (talk) 14:56, 26 December 2007 (UTC)

Stellar Structure

I cleaned up the stellar structure section a bit, most notably the incorrect statement that a core temperature of 107 K is necessary to maintain the equilibrium in a star. (Protostars and, for that matter, the Earth's atmosphere are in hydrostatic equilibrium at much cooler temperatures.)

Thank you.—RJH (talk) 17:25, 23 January 2008 (UTC)

The stellar structure section is generally excellent, but it links to the stellar structure article as the "main article", even though the linked article is much shorter and is essentially a little bit of text around the stellar structure equations. This seems incongruous to me. Either (1) the bulk of the stellar structure section on the stars page should be moved to the stellar structure page and a shorter summary written for here, (2) the different content on the stellar structure page ought to be moved onto the stars page and the stellar structure page deleted, or (3) the link ought to be changed to say something like "more information" instead of main article, and the stellar structure page should be improved (and possibly renamed). Any thoughts? I don't want to make a drastic change unilaterally. Ashill (talk) 02:36, 23 January 2008 (UTC)

The "main article" link in the structure section was pointed to the stellar structure page with the expectation of that page growing and improving in the future. Many of the astronomy "main article" pages linked from here are in need of improvement, but my feeling at the time was that the improvement should begin by bring this core topic/vital article page up to featured article status. (Which it is now.) I think the stellar structure page should expand on the summary content on this page, rather than trimming down this page. If you perform the latter then I think this page will no longer be considered as "comprehensive"; one of the featured article criteria. I don't see any particular urgency in changing the link or the content on this page. But I would really like to see the linked articles be improved and expanded.—RJH (talk) 17:25, 23 January 2008 (UTC)
Makes sense. I'll try to work on the stellar structure page soon. I agree that there's no urgency, but it was misleading. I will put a note on the stellar structure page (for now) that there's more detail on the stars page. Ashill (talk) 21:59, 23 January 2008 (UTC)
That would be great. Thanks.—RJH (talk) 18:18, 28 January 2008 (UTC)

Main Sequence Stars

I have noticed that in the article it says that Main Sequence Stars are also called dwarf stars, which is incorrect as only some stars in the main sequence are dwarf stars. For example, a Blue Giant is a Main Sequence Star.—Preceding unsigned comment added by 162.115.172.120 (talk • contribs)

I believe that in this context the term "dwarf star" is used to describe a star that has a "normal" size for its mass. So a Blue Giant is also a dwarf star. It's an unfortunate term.—RJH (talk) 22:20, 6 April 2008 (UTC)

Maybe it could just be worded differently somehow, because I could also see confusion arising when dealing with a "white dwarf" star, where it could be perceived as part of the Main Sequence when it really isn't. —Preceding unsigned comment added by 162.115.172.120 (talk) 00:53, 11 April 2008 (UTC)

It doen't make any sense to me either, but any star in the main sequence is technically considered a dwarf. Why there are white dwarfs and black dwarfs too is incomprehensible to me. Sorry, but that's how it is. J.delanoygabsadds 01:01, 11 April 2008 (UTC)
See Stellar Classification#Yerkes spectral classification for the description of the so-called "luminosity classes". "Dwarf" means a star of luminosity class V (five), also known as a main sequence star. "White dwarf" is something else entirely, just to keep you confused. Like many terms in astronomy, it's a collection of historical artifacts because these things were all named before anyone knew what was going on physically, and the arcane names have stuck around. It's a shame, but that's the way the field is. "Black dwarf" is an uncommonly used term, largely because of the possibility for confusion with white dwarfs and dwarf stars. I'll try to clean up the language in this article to clarify things a bit, but it comes down to confusing, poorly chosen nomenclature that we all use. ASHill (talk) 05:01, 11 April 2008 (UTC)
I changed dwarf star, which was a redirect to main sequence, to a page explaining the various uses of the term dwarf in the context of stars. ASHill (talk) 05:33, 11 April 2008 (UTC)
If the term causes confusion, then perhaps black dwarf ought to be merged with the white dwarf article.—RJH (talk) 14:40, 11 April 2008 (UTC)
I don't think that's necessary; even though the term is not one I've often heard or ever used myself, the black dwarf page is very clear about what it means and it does have a somewhat distinct meaning from white dwarf. ASHill (talk) 15:25, 11 April 2008 (UTC)

My apologies if this is the wrong place to ask a question, but this paragraph has me perplexed and curious: "The duration that a star spends on the main sequence depends primarily on the amount of fuel it has to burn and the rate at which it burns that fuel. In other words, its initial mass and its luminosity. For the Sun, this is estimated to be about [10 the power of 10] years."

100 Billion years, if my math is correct. A 10 with 10 zeros attatched. Given the age of the universe, this comes as a bit of a surprise. Perhaps a reference? —Preceding unsigned comment added by Luciusmichael (talk • contribs) 03:07, 7 July 2008 (UTC)

10 to the power of 10 is actually a 1 with 10 zeroes - 10 billion years in other words. This is the correct figure for our Sun. But thanks for checking - sometimes mistakes make it in and its good to keep your eyes open. PhySusie (talk) 03:15, 7 July 2008 (UTC)
For a reference, see: Main sequence#Lifetime —RJH (talk) 15:00, 7 July 2008 (UTC)

I totaly agree that they shouldn't put the fate of the Earth in the article. Since we still don't have a 100% picture on the Earth to Sun relationship. — Preceding unsigned comment added by Karicats7 (talk • contribs) 20:50, 14 March 2012 (UTC)

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