Talk:Star

Earth's fate

There's been a bit of back and forth about a recent result regarding the Earth's fate (in the Post-main sequence section). I loathe to accept a new paper (even in a journal) as fact, and I don't think the fate of the Earth or the exact maximum radius of the Sun as a red giant is at all settled.

However, is the fate of the Earth even worth including in this article? Mentioning the Sun as an example star is surely useful, but I'm not sure we need to include the Earth's fate (especially since it's also discussed in Sun, where I think it's more relevant). Ashill (talk) 03:54, 25 March 2008 (UTC)

Yes I agree. Discussion of the Earth's fate is probably superfluous here, or at least has an unnecessary level of detail. The Earth#Future section also covers the topic.—RJH (talk) 15:38, 25 March 2008 (UTC)

Done. Ashill (talk) 14:19, 27 March 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.delanoy^gabs_adds 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)

reflist box

A user put the reflist in a box. I undid the revision because it makes it much harder to see read the references, particularly on a mobile device. ASHill (talk) 09:49, 15 April 2008 (UTC)

Introduction

"...a star shines because thermonuclear fusion in its core releases energy that traverses the star's interior..." I question the use of "energy" cause it seems to mean that energy is a kind of "thing or object" by itself radiating from the core and it does not well explained why the star shines. —Preceding unsigned comment added by Chiloa (talk • contribs) 15:26, 4 May 2008 (UTC) Chiloa (talk) 15:33, 4 May 2008 (UTC)--Chiloa (talk) 15:33, 4 May 2008 (UTC)

I'm unclear what the objection is; energy does traverse the star's interior and then radiate (travel) out into space in the form of electromagnetic radiation.

The fusion releases energy; the release of that energy is shining. ASHill (talk | contribs) 15:35, 4 May 2008 (UTC)

Why not simply use "form of electromagnetic radiation" rather than "energy"?--Chiloa (talk) 15:41, 4 May 2008 (UTC)

Some of the energy would be in the form of heat conduction, and convection, and non electromagnetic radiation, such as neutrinos. Graeme Bartlett (talk) 22:11, 4 May 2008 (UTC)

Main sequence

• "As a consequence, in order to maintain the required rate of nuclear fusion at the core, the star will slowly increase in temperature and luminosity."

I don't understand this sentence. Is the star really "required" to maintain a rate of nuclear fusion? The rate of nuclear fusion is surely determined by pressure and temperature, is it not? Causality, right? This sentence makes it sound as if the star actively increases its temperature and luminosity to maintain its rate of fusion, which, as an inanimate object, doesn't make much sense - it seems backwards. Could somebody either correct or explain this in the article? Thanks. AJKGORDON«» 14:49, 22 August 2008 (UTC)

The rate of fusion required to maintain an equilibrium configuration. WilyD 14:53, 22 August 2008 (UTC)

No, that still doesn't explain the sentence above. At least not to me, a layman. The way the current sentence reads is that the star will slowly increase in temperature and luminosity to maintain the required rate of nuclear fusion. Why does it have to maintain that rate? Why is it required? What's making it "maintain an equilibrium configuration"? AJKGORDON«» 18:33, 22 August 2008 (UTC)

Otherwise it'll loose heat faster than it produces heat, and start to collapse; then density will go up, fusion rate will go up and it'll heat up. Things move to stable configurations and then stay there because they're stable. WilyD 18:36, 22 August 2008 (UTC)

Would it make more sense to say the following?

As a consequence, in order generate the energy needed to maintain equilibrium, the star will slowly increase in temperature and luminosity.

The subject is covered in more detail on the main sequence article.—RJH (talk) 20:11, 25 August 2008 (UTC)

Can stars have rings?

Are there any stars that have rings? YouthoNation (talk) 18:15, 30 September 2008 (UTC)

Yes: Debris disk—RJH (talk) 19:09, 30 September 2008 (UTC)

Planetary system

Should a sub-section on "Planetary system" be added to the Characteristics section? While it is not really a physical characteristic of a star, it is related to the star's evolutionary history. Thus it might be worthwhile summarizing. (I'm not sure whether "Planetary system" is the best name, as some may only consist of a debris disk, for example.)—RJH (talk) 16:41, 20 November 2008 (UTC)

The lead

The opening was desperately in need of a re-write, please do not edit war over this, explain whatever POV you may have here on the talk page. the opening claimed stars are massive and failed to point out they are part of a solar system in many cases and part of a galaxy in many cases, removing such added information is clearly unhelpful. My own perception is that the lead was one of the most badly written I have come across on wikipedia and I am mystified as to why one user would revert back to the poor opening. Thanks, SqueakBox 22:42, 20 November 2008 (UTC)

Hall, with your edit warribng and your refusal to discuss your edit warring and your poor edit summaries you appear to think you own this article. You do not own it so please stop acting as if you do. Thanks, SqueakBox 14:03, 21 November 2008 (UTC)

Well, at risk of starting a diplomatic incident, I'd like to suggest you take a break and come back when you've calmed down a little. I wrote some legitimate issues on your talk page which you apparently just removed... without response. Here is what I wrote:

Please stop making additions to the lead that are not covered in the article. See WP:LEAD: the lead should summarize the article. The article is also about stars, rather than star systems, and so discussion of planets is besides the point. Your additions are also unsourced and thus go against wikipedia policy. Thank you.—RJH (talk) 23:47, 20 November 2008 (UTC)

I think you're being provocative and argumentative. The last time I checked this talk page, there was no discussion regarding the lead. Thus I am starting to think our dispute may be a timing issue.

I welcome a discussion that leads to article improvements. But I think I do have some legitimate concerns over your edits not meeting FA criteria, being off topic and unsupported, and not necessarily being an improvement.—RJH (talk) 15:40, 21 November 2008 (UTC)

The new lead is terrible as well though. It's certainly not better. It is not an essential characteristic of stars that they're generally found in and around galaxies. WilyD 14:05, 21 November 2008 (UTC)

Looking to write a comprimise version, the original lead was roughly what I intended to write but more eloquent. While most stars are probably orbited by planets, this isn't established yet (~15% is probably the rate established). Further, while stars are often in galaxies (and far less often in star clusters - not sure on that rate), this is fairly incidental to their fundamental character. Certainly some unknown fraction of stars are not, and being in a galaxy has very little effect on a star. WilyD 14:14, 21 November 2008 (UTC)

Thanks, I completely agree. My feeling on the matter is that the article is about stars and should focus on those objects. Whether stars have planets and/or belong to galaxies is a somewhat secondary matter and doesn't rate priority placement in the lead. The topics aren't even significantly covered by the article body. The statement about planetary systems is not properly sourced, and that is an issue for me as well. The current lead has gone through many edits and has been well reviewed. It may not be perfect, but significant re-edits that are not an improvement have questionable weight.—RJH (talk) 15:42, 21 November 2008 (UTC)

Bugged by a para

This paragraph irritates me, for something like shooting-mites-with-cannon-logic:

As well as certain constellations and the Sun itself, stars as a whole have their own myths.[23] They were thought to be the souls of the dead or gods. An example is the star Algol, which was thought to represent the eye of the Gorgon Medusa.

Strictly the third sentence fails, and the second sentence is far irrelevant. If Medusa is a myth, that doesn't mean the eye of Medusa is a myth. That means that the eye of Medusa is a mythical representation, but the eye of Medusa has no elaborate story that antique Greeks told their antique Greek children. And how can the eye of Medusa be a soul of the dead or be a god? What's the point, with that sentence? A sentence including myth, Medusa, eye of Medusa and mythical representation is most certainly needed but the paragraph might need some reformulation in order to get the logic right. ... said: Rursus (Bork, Bork!) 09:58, 3 January 2009 (UTC)

OK, now I see what is the error! "Myth" acc2 WP itself is a story a saga, but in transfered meaning "myth" can also mean "mythical thing", and if Medusa is a mythical being, then the eye of Medusa is a "mythical subcomponent" of the mythical Medusa. But, nevertheless, the logic becomes confused by switching to and from the primary and secondary meanings of "myth". ... said: Rursus (Bork, Bork!) 10:06, 3 January 2009 (UTC)

Factual error?

This sentence is probably factually wrong:

Later the English astronomer John Flamsteed came up with a system using numbers, which would later be known as the Flamsteed designation.

I'll make a try to find a source (prob Tirion/Uranometria 2000.0) for that Lalande invented this numbering, adding it to his French version of the Flamsteed catalogue. ... said: Rursus (bork²) 10:34, 3 January 2009 (UTC)

Lalande invented it, acc2 Tirion/Uranometria 2000.0 (ISBN 0-943396-14-X and ISBN 0-993396-15-8). Just a few minutes... ... said: Rursus (bork²) 21:33, 3 January 2009 (UTC)

Fixed. ... said: Rursus (bork²) 21:47, 3 January 2009 (UTC)

I think I might be wrong in this (as well as Tirion/Uranometria 2000.0 being wrong). Many sources claim that the unauthorized Flamsteed catalogue contain these numbers, and it might be that Tirion's working group (Tirion, Lovi and Rappaport), didn't have access to this catalogue version. ... said: Rursus (bork²) 11:02, 30 January 2009 (UTC)

I've decided I was wrong in this, claiming that the text on IAU and on SEDS take preceedence before Tirion, because Tirion's latest source was dated 1986, while SEDS uses Bakich, 1995, Cambridge. I'll fix it. ... said: Rursus (bork²) 11:26, 30 January 2009 (UTC)

• IAU on this
• SEDS on this

... said: Rursus (bork²) 12:34, 30 January 2009 (UTC)

Fixed (for this time). ... said: Rursus (bork²) 19:02, 30 January 2009 (UTC)

Star From Wikipedia, the free encyclopedia Jump to: navigation, search This article is about the astronomical object. For other uses, see Star (disambiguation).

heavy elements not produced by stellar cores

By heavy I mean elements heavier than Fe-56 that don't get produced inside stellar cores. As the heavier nuclei are less tightly bound than the Fe nucleus, the dense core environment tends to make them slide back to iron when produced by chance. I am not a good enough in the element abundancy subject but aren't these crazy heavy elements mostly produced during the blow-up of dying Suns(like novae, etc.)? Correct me if I am wrong.

My understanding is that the heavy elements are mostly created by supernovae and red giants. C.f stellar nucleosynthesis. This might be worth mentioning in the 'Nuclear fusion reaction pathways' section. Thanks.—RJH (talk) 22:57, 9 March 2009 (UTC)

Mass is not converted to energy

The relation E = mc^2 says that mass and energy are two different manifestations of the same thing and only exist together, so it is not correct to say one is converted into the other. We should re-word that part of the article (under the heading "Nuclear fusion reaction pathways".) 69.140.12.180 (talk) 03:56, 31 May 2009 (UTC)Nightvid

What alternate wording would you suggest (that does not immediately result in increased confusion)?—RJH (talk) 17:23, 1 June 2009 (UTC)

Technically, the anonymous user has a point, although I don't think there is any risk of confusion in this context. You could change "energy" to "thermal energy", which would be more correct. Timb66 (talk) 22:47, 1 June 2009 (UTC)

I understand, but his point about mass/energy being the same thing brings up the new question of what do we call that "thing" and how do we avoid confusing the lay reader by doing so? Thus my question. Anyway I changed the wording slightly to avoid the use of the word "converted". Thanks.—RJH (talk) 15:50, 2 June 2009 (UTC)

Chemical Composition of Stars

In "Characteristics" section, under "Chemical Composition" subheading, the first sentence says "When stars form they are composed of about 70% hydrogen and 28% helium, as measured by mass". This is wrong. The reference given is an unrelated press release from ESA. These percentages are for the current H and He content of the Sun, and not of past composition of the Sun during its formation or of another star.

True, it should probably be a range instead. How about, "...70–74% hydrogen and 24–28% helium..."? Or perhaps you could suggest a better reference.

I added a second citation and modified the values slightly to match. If you have a better citation, please let us know.—RJH (talk) 20:24, 1 June 2009 (UTC)

(Too bad I cannot remove the false information. Wikipedia is not editable anymore unless I sign in. A topic on which so much scientific information is available on the web contains unforgivable mistakes. It seems 10 year olds can edit wiki articles so long as they sign in, while scientists cannot unless they provide their personal info. It seems the best way to create an encyclopedic database.) —Preceding unsigned comment added by 128.12.172.209 (talk) 23:59, 31 May 2009 (UTC)

You do not need to use your name for your account sign-in. I choose to just use my initials, while others select purely anonymous identifiers. Hint: it also helps to be civil here and not immediately slam the other editors.

Since you mention "unforgivable mistakes", I can only assume you have identified multiple egregious errors that you have yet to describe. Well there is always room for improvement, so please fill us in. Thanks.—RJH (talk) 17:15, 1 June 2009 (UTC)

Mythologies

It seems that the section of Star designations treats myths erroneously.

1. Stars have no myths by themselves, in a few cases the brightest star got the name that originally belonged to an entire constellation, such as Capella (only an independent constellation in the antiquity), Arcturus and Procyon, but the attached image "little she-goat", "bear-watcher" and "fore-dog", mostly belonged to an entire constellation.

2. It also seems, among others from J. H. Rogers' investigations, that the image was primary for the constellations, and the myth was something borrowed from the culture and attached in order to fit to the image.

This stars-representing-souls stuff and individual-stars-having-myths stuff seems to be extrapolations without any factual foundation. ... said: Rursus (bork²) 12:29, 23 June 2009 (UTC)

I agree with you, which is why I tagged those sentences as needing citations. It was my hope that the original editor would address those, otherwise I was going to yank them out after sufficient time had passed.—RJH (talk) 16:44, 23 June 2009 (UTC)

Reverted re-org.

I reverted the recent re-organization primarily because the original article had a certain explanatory flow that was disrupted by the section relocations. I think the article should explain certain facts before using them in a description. For example, the existence of white dwarfs is explained in the section on formation and evolution before their classification is listed. If you reverse the order, then the reader is left wondering what is a white dwarf... up until it is explained. This flow was created in order to satisfy the FAC.—RJH (talk) 16:51, 17 December 2009 (UTC)

Here's one possible re-organization that would maintain a sequence of explanation while including sub-groupings in the ToC:

• Observation history
• Unit of measurement
• Designations
• Formation and evolution
  • Protostar formation
  • Main sequence
  • Post-main sequence
  • Massive stars
  • Collapse
• Characteristics
• Populations
  • Classification
  • Distribution
  • Variability
• Energy generation and emission
  • Nuclear fusion reaction pathways
  • Structure
  • Radiation

What do you think?—RJH (talk) 16:32, 18 December 2009 (UTC)

10 well known stars

1.sun 2.sirius 3.pollux 4.arcturus 5.aldebaran 6.rigel 7.pistol star 8.antares 9.mu cephei 10.vy canis majoris-is a hypergiant star