Talk:Star/Archive 1

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)

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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)

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

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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)

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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)

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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)

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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.

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)

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)

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 [[1]].

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)

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)

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.[2] :-) — 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.[3] 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.[4]

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)

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)

• • Your topic title states: Size, while your text talks about Mass? Seems to me that you are confusing these two things..
    • full stars (orange dwarfs, yellow dwarfs (Sun), and higher), or a 'dead' star (white dwarf)
    • *Hydrogen-fusing bottom-limit
    • Red dwarf between 80 - 65 jupiter masses
    • *lithium-fusing bottom-limit
    • Brown dwarf between 64 - 13 jupiter masses
    • *deuterium fusing bottom-limit
    • Sub-brown dwarf or Planemo 12 jupiter masses and lower

• • I think these articles might be of use for this topic: List of smallest stars and List of lightest stars (includes red & brown dwarfs).
    If you would include 'dead' stars, neutron stars are the smallest.
  • -- User:Patrick1982 01:40, 24 Aug 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)

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)

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)