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#32
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When the sun becomes a white dwarf why will it take SO long to cool off?
"SW" == Sam Wormley writes:
SW jacob navia wrote: Excuse me but what is "degenerate" in a white dwarf? I mean they are made of normal matter, albeit very concentrated, not neutron stars, nor quark stars, just balls of iron and heavy elements at very high densities. Nothing degenerate at all. SW Besides being degenerate, white dwarf are mostly carbon and SW oxygen. I think that's only true of some WDs. The composition of a WD depends upon what its progenitor mass was. Stars less massive than the Sun I believe are expected to become helium WDs because they don't have the mass to initiate the fusion of He to C. -- Lt. Lazio, HTML police | e-mail: No means no, stop rape. | http://patriot.net/%7Ejlazio/ sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html |
#33
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When the sun becomes a white dwarf why will it take SO long to cool off?
SW ...white dwarf are mostly carbon and oxygen.
In article , Joseph Lazio writes: I think that's only true of some WDs. The composition of a WD depends upon what its progenitor mass was. Stars less massive than the Sun I believe are expected to become helium WDs because they don't have the mass to initiate the fusion of He to C. Joe is correct, of course. I don't know what the dividing line is; those courses were a long time ago! I vaguely recall it's quite a bit less than a solar mass but could easily be wrong. I don't suppose it's too much lower than a solar mass, though, or no helium white dwarfs would yet have formed. White dwarfs with helium and even hydrogen _atmospheres_ exist, but that doesn't necessarily reflect the interior composition. -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
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