Massive Stars

Question 1

How big?

Answer 1

> 10 solar masses

use up hydrogen quickly, short lifespan

Question 2

what happens at first?

Answer 2

core begins to collapse

temp is sufficient for helium to overcome electrostatic repulsion, fusion occurs.

Question 3

What happens as a result of fusion?

Answer 3

Star expands, becoming a red giant.

Question 4

How is iron core formed?

Answer 4

more massive nuclei fuse in the core, new elements are distributed in a series of fusion layers.
fusion of helium, carbon and oxygen tale place in the core of hydrogen
inert iron core is formed, decrease in radiation pressure allows gravitational collapse to occur.

Question 5

red supergiant formation

Answer 5

fusion of elements heavier than iron take place in stars core

Question 6

What happens due to lack of radiation pressure

Answer 6

supernova - an implosion of a red supergiant following the formation of sufficient iron in its core. outer core and outer layer bounce off inner core and are ejected into space leaving an inert core.

Question 7

what happens if core is >1.44M but <3M?

Answer 7

neutron star is formed

Question 8

what happens if core is >3M

Answer 8

black hole is formed

Question 9

What are characterisitcs of black holes?

Answer 9

escape veloctiy > speed of light
small mass
no fusion
absorbs light