How long until Sol, once it becomes a White Dwarf, goes completely cold and generates no more heat or light at all?
2006-11-19 05:34:58 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
A VERY long time. White Dwarfs cool slowly.
What you are really asking is "what is the white dwarf cooling function"? As written your question does not make a lot of sense because as long as the remnant has a finite temperature it will radiate like any black body! Pick a brightness that means "no light at all" to you and then you can calculate it.
Table 6 of this paper: http://www.edpsciences.org/articles/aas/pdf/1996/07/ds869.pdf
lists cooling times for a 0.6 M_sun white dwarf to reach various luminosities (starting at 1/10th L_sun to 1/50000th l_sun) are given under two different models. Note that even at 10^12 years (1 trillion years or about 75 times the age of the universe) this thing is still 1/50000th as a bright as a sun. Since it also has a radius about 1/100th of the sun it will still have a surface temperature of about 3900K; which is still hotter than the coolest main sequence stars and about twice as hot as a terrestrial blast furnace, so still VERY bright, although in total luminosity it will be about 1/10th as bright as a faintest main sequence star (hotter but dimmer because it is much smaller). To me, a trillion years is essentially forever.
2006-11-19 14:02:19 · answer #1 · answered by Mr. Quark 5 · 0⤊ 0⤋
The Sun will become a white dwarf in about 5 billion years, give or take a billion.
2006-11-19 05:41:08 · answer #2 · answered by eri 7 · 0⤊ 0⤋
i have no ide whate you meen do it beeter
2006-11-19 05:38:15 · answer #3 · answered by Patrick L 2 · 0⤊ 3⤋