NATS 1880 Chapter Notes -Galactic Habitable Zone, Rare Earth Hypothesis, Seasonality
Document Summary
Nats1880 chapter 11: habitability outside the solar system . All stars form from the collapse of a large cloud of gas (h and he) and in a few million years, form either a multiple star system or a single star with a planetary system. Stars are born when h begins to fuse to he in the core. When a protostar forms, it creates radiating hear due to collapse of gas. A star is a ball of has powered by nuclear fusion and held together by its own gravity. Stars spend 90% of their life fusing h to he on the main sequence. *main sequence the prominent line of points (representing main-sequence stars) running from the upper left to the lower right on an h-r diagram. *main sequence stars stars whose temperature and luminosity place them on the main sequence of the h-r diagram. Main-sequence stars release energy by fusing hydrogen into helium in their cores.
