Talk:Chandrasekhar limit
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[edit] Origin of Mass limit
While known as Chandrasekhar limit, there is work on white dwarf mass limits that predates Chandrasekhar, namely Wilhelm Anderson of Tartu University and Edmund Clifton Stoner of Leeds University - see also NATURE|Vol 440|9 March 2006 p148: "Giants of physics found white-dwarf mass limits"
[edit] Usage of a phrase
"The limit was first discovered and calculated by the Indian physicist Subrahmanyan Chandrasekhar in 1930, during his maiden voyage to Britain from India."
I've never seen the term "maiden voyage" applied to anything but a boat/ship; certainly not a person (or a male, for that matter!) Anyone have direct or specific knowledge regarding the usage of this phrase?
[edit] Heat or radiation?
"The heat generated by a star pushes the atmosphere of the star out." I always thought it was mainly radiation that supports stars?
- Technically it is radiation pressure* that prevents a star from collapsing under gravity but I think 'heat' is being used here as thermal radiation. *Radiation pressure being the actual pressure exerted outwards by the photons generated during the nuclear fusion. Joanna Goodger 15:04, 24 January 2006 (UTC)
"ergs"?? "dynes"?? As a product of 1960's and 1970's Mechanical Engineering education at the Universities of Illinois and Florida, having turned to Nuclear Physics in the 1980's at FSU, and now being a teacher of Physics....I have come to appreciate the SI system (the modern version of the metric system, now used by most countries in the world)....please use it in your documents! Thanks!198.146.57.2 14:51, 27 July 2006 (UTC)
[edit] Misconceptions regarding white dwarf collapse
I have corrected several misconceptions regarding white dwarf collapse, namely:
The old idea that white dwarfs which have reached the Chandrasekhar limit and started to collapse are the progenitors of Type Ia supernovae, was superseded in the 1960s by the theory that runaway nuclear fusion is triggered by increasing interior density in carbon-oxygen white dwarfs prior to their attaining this limit.
The hypothesis that white dwarfs collapse into neutron stars during the course of a Type Ia supernova explosion is now regarded as being incorrect; neutron stars can be formed in Types Ib, Ic, or II supernovae (whose progenitors are far more massive than white dwarfs - over about 12 solar masses: they are called "massive stars" whereas the white dwarfs whose lives end in type 1a supernovae are about 1.4 solar masses), but most astrophysists now believe that in a Ia supernova the white dwarf is obliterated, leaving nothing behind except the plasma and radiation of the supernova remnant.
- This is probably true, but it (and everything else on Wikipedia) needs a citation added. Also, please sign your postings to the talk page by adding ~~~~ to the end of your post. Richard B 18:55, 4 November 2006 (UTC)
[edit] Controversy on Chandrasekhar - Eddington relations
In a review of Arthurs I. Miller's biography of Subrahmanyan Chandrasekhar published in Physics Today (feb 2006, p.53) Kameshwar Wali shows sharp disagreement with the point of view expressed by Miller as regards the relations between Chandra and Eddington, and the attitude of the later and other Oxbridge astrophysicists towards Chandra's white dwarf theory, based on his own numerous and extensive conversations with Chandrasekhar that furnished him with the material for Chandra's biography that Wali himself wrote about fifteen years ago. To a collegue in India that he wanted to persuade to come and visit Cambridge, Chandra wrote, among other: " In Cambridge I get the utmost sympathy and encouragement for my work. Fowler, Eddington and Dirac are all extremely kind and encouraging and even spend quite considerable time to clear up some difficulties that I may come across." So the least that can be said is that the case needs further study before being filed in the catalogue of histories about sectarist, not to say racist, attitudes of european scientists towards an indian colleague in those times.
[edit] Wrong formula
Surely it can't be correct to express the limiting mass as the sum of the Sun's mass and the formula. The only way something like that could arise would be as a part of an expansion around the solar mass, which there is no indiaction of here. Is the "+" supposed to be multiplication instead? The article itself makes use of the +, though, using it to derive a limiting mass for a neutron white dwarf of one solar mass. It is hard to see how a star with no electrons could be supported by electron degenerace pressure. I don't have the correct formula at hand, but this needs to be fixed. Oh, and the "definition" given as an approximate equation in the beginning should also be fixed. Amaurea 15:48, 20 November 2006 (UTC)
