Question

Please help with #3 in the form ex: t(main sequence) ~ 10^10 years. Number 3 has a minimum of 1 billion years. If you could please help with 4a as well that would be much appreciated!

he earliest fossil records indicate that life appeared on Earth about a billion vears after the formation of the solar svstem. What is the most mass that a star could have in order that its life-time on the main- sequence is long enough to permit life to form on one or more of its planets? Assume that the evolutionary processes would be similar to those that occurred on the Earth, a) Use relations derived in class notes to relate the average central temperature, Tc in a star to the surface temperature, Te of a star. Your answer should be expressed in terms of these temperatures and either the mass, M, or radius, R, of a star. b) For a star 10 times more massive than the sun how does the ratio of the Tc to Te change?

Answer 1

The most mass that a star could have in order that its life - time on the main sequence is long enough to permit life to form on one or more of its planes For a long time, 150 solar masses can be considered to be the top end for stellar mass. However, the most massive star found comes in at 300 solar masses Assuming that the development & evolution of life is pretty much similar with life on earth, it's highly unlikely that life could originate on such a high - mass star, its life span is estimated to be little more than about 200 - million years Infact, that 300 - solar mass giant is already throwing off material as it works its way through the stages of fusion The life time of a star is proportional to the inverse cube of the mass so the Answer in a very approximate way is not