Supernovae Flashcards
What is a Type ll supernovae?
When a massive star core collapses at the end of its life, to form a neutron star or blackhole. They occur from population 1 stars
What is Type Ia supernovae?
When a white dwarf collapses because it goes over its mass limit due to mass accretion in a binary star system. This is the evolution of old, low mass stars and are therefore population ll.
How are supernovae energies estimated?
from the gravitational potential energy released. The mass released is approximately the mass of the star.
What happens to the supernova remnants?
They are ejected at several thousand kilometers per second. As the shell expands it sweeps up interstellar material and slows down. They expand for millions of years so fill up a large volume of the galaxy.
How are the supernovae remnants observed?
The shell travels faster than the speed of sound so a shock wave results. The shocked gas gets heated to a very high temperature which emits xrays due to bremstahlung - when the gas is decelerated it emits a photon. This causes a very low density, very high temperature gas observed as a weak x-ray emission through the interstellar space, especially in the spiral arms.
The remnants interact with magnetic field, rotating around the lines, giving synchroton radiation when the electrons spiral around the magnetic field. It is strongest at radio.
