ASTR 1102 Lecture : Astronomy Notes
Document Summary
The sun"s luminosity will rise to 1000 times its current level-too hot for life on. The sun"s radius will grow to near current radius if earth"s orbit. High mass main-sequence stars fuse h to he at a higher rate using carbon, nitrogen, and oxygen as catalysts. Greater core temperature enables hydrogen nuclei to overcome greater repulsion. Late life stages of high mass stars are similar to those of low-mass stars: High mass stars have convection to mix h in the core. Move right on the h-r diagram: types of pulsating stars. Ignite he in a non-degenerate core, unlike low-mass stars. With riding central temperatures, heavier elements(c, ne, etc. ) fuse . As high-mass stars expand and cool,, they can pass through the instability strip on the h-r diagram. Big bang made 75% h, 25% he; stars makes everything else. Cno cycle can change carbon into nitrogen and oxygen. High core temperatures allow helium to fuse with heavier elements.
