NATS 1880 Lecture Notes - Lecture 17: Galactic Habitable Zone, Light Curve, Main Sequence
27 Aug 2015
School
Department
Course
Professor
Document Summary
In a few million years, form either a: All stars form from the collapse of a large coud gas (largely h and he) A) multiple star system (with/without planets), or. B) a single star with a planetary system. A protostar first forms, radiating heat due to collapse of gas. Star is born when h begins to fuse to he in the core. A star is a ball of gas powered by nuclear fusion and held together by its own gravity hotter. Stars spend 90% of their life fusing h to he on the main sequence. When h has been used up in the core, the core contracts making it temporarily. The core becomes so hot that it can fuse he to carbon -> core helium burning . H can fuse to he in a shell outside the core causing the star"s envelope to swell.
