High Mass Stars ✨🤩

CNO cycle

While low mass stars fuse 4 H atoms to make He, high mass stars make He faster by turning C into N and O

helium capture

helium crashes into other atoms and makes heavier elements

Element abundance and causes

The Big Bang made 75% H, 25% He. Stars make most of everything else.

Low mass stars can only make elements as heavy as C (normally)

Shell fusion

Each time a high mass star runs out of an element to fuse in the core, that element moves outwards and fuses in a shell.

Supernova

the explosion of the outer layers of a massive star

Neutron stars

If the core is less than ~3 times the Sun's mass, the force of neutrons is enough to hold the core up from gravity: a: are the remains of high-mass stars after a supernova, about the size of a small city

T/F low mass stars can fuse and produce elements all the way up to iron(Fe) before transitioning into the red giant phase

false

High mass stars burn through elements quicker because the core temperatures are much higher compared to low mass stars, therefore atoms overcome repulsion much easier.

true

The Sun's radius will eventually reach the size of Earth's orbit when it becomes a red giant

true

Why does all fusion stop at iron (Fe)?

Iron does not release any energy when fused

what happens when the core temperature of a star rises enough for fusion to begin?

He fusion rises very sharply

How would the universe be different if H, rather than Fe, didn't release energy when fused

There would be no life on Earth and The periodic table would have far fewer elements

If a core of a massive star is ________ solar masses or higher, it will turn into a black hole after the star goes supernova

3

What happens to a high mass star each time it runs out of a higher element to fuse?

what happens when the core runs out of He to fuse?

Lighter elements move outwards and start fusing in shells

He fuses in a shell around the core