Re:Venus could have been habitable for billions of years (2019)
by btach on Wednesday March 24, 2021 @03:59AM
(#26564599)
(I'm not an astronomer, my understanding is not absolute, please correct if I'm wrong) I believe our Sun is a type G, yellow dwarf. A red dwarf is usually much smaller, if considering "red dwarf" being a type M, then usually no more than 0.6 solar masses, usually much smaller, and a tiiiiny fraction of the luminosity of Sol. Brown dwarfs are not massive enough to fuse hydrogen, where red dwarfs generally are. According to https://en.wikipedia.org/wiki/Red_dwarf, above 0.25 solar masses, they should evolve into red giants, otherwise will shrink into a white dwarf once hydrogen fusion is ceased. The universe isn't old enough to have any red dwarf of 0.25 solar masses to do so, however as their lifespans are so long.
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