Supernova final

Question 1

What is a supernova?

Answer 1

Explosion of a star
Largest explosion that takes place in space
~10 supernovas/second in Universe
~1 supernova/50 years in galaxy the size of the Milky Way

Question 2

What causes a supernova?

Answer 2

Change in the star’s core.
Star fusion: balance between nuclear fusion outward pressure and inward gravitational pull. When fusion slows, outbound pressure drops and the core heats and condenses under its own gravity until it explodes

Question 3

Type Ia Supernova

Answer 3

Close binary system where a white dwarf takes matter from its companion star. Reaches 1.4 solar masses. 10 billion solar luminosities.

Question 4

Chandrasekhar Limit

Answer 4

1.4 solar masses. Maximum mass that a white dwarf star can have and still remain a white dwarf. Above this limit, electron degeneracy pressure is not enough to prevent gravity from collapsing the star

Question 5

Standard Candles

Answer 5

Due to the 1.4 solar mass and standard brightness of Type Ia supernovas, they are considered “standard candles”
Astronomers can use them to measure distances in the Universe. Used to figure our the rate of expansion.

Question 6

Type II Supernova

Answer 6

Star runs out of nuclear fuel (hydrogen and helium). When it runs out of hydrogen, if fuses helium, then carbon, neon, etc.
Gradually heavier elements build up at the center of the star, with lighter elements toward the outside of the star.

Question 7

Elements from Type II supernovas

Answer 7

As the star collapses, nuclei are crushed together and elements heavier then iron form. Shockwave passes passes outward - creates heavier elements like gold, silver, platinum, uranium, etc.

Question 8

Famous supernovas

Answer 8

SN 1054 –> Crab Nebula
1572 Tycho’s Supernova
SN 1604