Talk:White dwarf

message: I was curious as to the difference between Red dwarfs, Brown dwarfs and White dwarfs.  Each of the three articles rarely or never mention the others, although it's natural to assume there's a similarity.  From what I've read of the three:
• Red dwarfs are full-on  stars, just small, maybe can't do helium fusion.
• Brown dwarfs are smaller still, can't even fuse hydrogen, but can participate in some lame fusion reactions, if they're lucky.  Their surface temperatures range down to room temperature!  Their sizes range down to gas giant planets.
• White dwarfs are supernova remnants; totally different from the other two.  They often have surface temperatures comparable to stars (hence 'white') from residual heat; can't do fusion.  If they get bigger, 1.44M☉, they become neutron stars  (after maybe a supernova).  (And neutron stars similarly become black holes beyond 3M☉.)
I'd prefer if a professional could supply and correct these guesses of  mine in the article, maybe a separate section.  Also the other two articles.
OsamaBinLogin (talk) 20:35, 11 May 2022 (UTC)
replies: text: White dwarfs are not supernova remnants, just the remnants of ordinary stars, although possibly supernova progenitors.  See also black dwarf and blue dwarf.  Not sure we can explain every type of stellar object with "dwarf" in the name in every other article with "dwarf" in the name.  So long as each article is clear about what it is, that would hopefully be enough.  Perhaps best not to assume there is a similarity, certainly no similarity to green dwarf.  However, for an overview of the term "dwarf" when applied to stars and star-like objects, see dwarf star, perhaps something that could be linked from other articles more often.  Lithopsian (talk) 20:48, 11 May 2022 (UTC)
replies: text: Couldn't find reference in Wikipedia to "green dwarf" referenced in your answer. Are you messing  with us? If so, carry on...more power and so on....Makermark (talk) 21:44, 20 August 2022 (UTC)
thread_title:  versus Red and Brown flavors 

message: Aren't atomic nuclei also collections of matter surpassing the density of white dwarfs? 174.103.211.189 (talk) 23:08, 26 December 2023 (UTC)
replies: text: The article doesn't say that white dwarfs are the densest collections of matter. The only reference to the word 'densest' is this sentence: 'White dwarfs are composed of one of the densest forms of matter known, surpassed only by other compact stars such as neutron stars, quark stars (hypothetical), and black holes.' And I think it's fine the way it is. Nuclei could arguably be considered a form of matter, but I think it's clear from the way it's phrased that they mean matter in the macroscopic sense of the word. MathewMunro (talk) 03:43, 7 January 2024 (UTC)
replies: text: Thanks. That's what I figured. 74.135.194.87 (talk) 18:28, 19 January 2024 (UTC)
thread_title:  Densest collections of matter 

message: I am reviewing this article as part of WP:URFA/2020, and initiative to evaluate older featured articles to ensure that they still meet the FA criteria. I have some concerns with this article:
*There are numerous uncited passages, including whole sections at the end of the article. 
*The gallery at the end of the article should be evaluated. Can these been used in other sections of the article instead, or perhaps removed?
*There are references that need to be properly formatted, especially the last three. Has anyone checked to ensure that they are high-quality sources?
Is anyone intersted in fixing up the article? If not, I will nominate this to WP:FAR in a couple of weeks. Z1720 (talk) 15:10, 26 January 2024 (UTC)
thread_title:  [[WP:URFA/2020]] 

message: The paragraph says that radiative heat transfer is low "because any absorption of a photon requires that an electron must transition to a higher empty state, which may not be possible as the energy of the photon may not be a match for the possible quantum states available to that electron"
I don't think the lack of absorption is important, but the lack of emission is. If thermal radiation wouldbe emitted, the thermal energy would go somewhere. It would probably be absorbed in the outer layers, or be emitted, leading to fast cooling of the core.
But I think in the same way as the lack of empty states prevents absorption, it is also preventing thermal excitation of electrons to energy levels from where they could emit radiation. Emilo Alberto (talk) 11:21, 8 March 2024 (UTC)
thread_title:  Radiation and cooling: