Astrophysics - Life cycle of a star Flashcards
After main sequence, what happens to a sun-like star? What do we classify as a ‘sun-like’ star?
A sun-like star has a mass up too about 8 solar masses
Main sequence -> Red giant -> White dwarf and a planetary nebula.
After main sequence, what happens to a star heavier than the sun but less than 20 solar masses?
Main sequence -> Red super giant -> Supernova -> Neutron star
What are the conditions for a star to become a black hole?
Its mass > 20 solar masses
Describe a black hole
A region of space where the escape velocity, Vesc, is greater than the speed of light
What is the schwarzschild radius also known as?
An event horizon
When is a black hole formed?
A giant star collapses into a blackhole when the force of gravity is > electron degeneracy
What is a gamma ray burst; when does it occur?
When a giant star collapses into neutron star or a black hole, an incredibly intense, highly collimated beams of gamma is emitted.
What would happen if a gamma ray burst hit earth?
Everything would die
What is the life cycle of a star before main sequence?
Molecular cloud -> Protostar -> Pre-main sequence -> Main sequence
When does a type 1A supernova occur?
In a binary star system with a white dwarf
How is a type 1A supernova formed?
The white dwarf pulls the mass off the usually giant star
It gathers enough mass so gravity> electron degeneracy
The white dwarf implodes
What can we infer from a Type 1A supernovae light curve?
They all have the same light curve, absolute magnitude can be determined and so type 1A supernovae are standard candles.
