Question: A surface explosion on a white dwarf, caused by falling matter from the atmosphere of its binary companion, creates what kind of object?

Answer: nova

Question: The Chandrasekhar mass limit is:

Answer: 1.4 solar masses.

Question: For a nova to occur, the system must have already been a(n):

Answer: mass-transfer binary.

Question: The total energy emitted by the brightest nova explosions is about:

Answer: a million Suns.

Question: Why are neutrinos from a type II supernova detected before photons?

Answer: Neutrinos escape from the star quickly because they hardly interact with matter; photons are delayed by interactions with matter.

Question: Novae always occur in a close binary star system.

Answer: True

Question: Unlike supernovae, novae can explode more than once, increasing their luminosity by thousands of times.

Answer: True

Question: An iron core cannot support a star because:

Answer: iron cannot fuse with other nuclei to produce energy.

Question: Beyond the formation of iron, nuclear energy can be produced only by:

Answer: fission of heavy nuclei back toward lighter ones.

Question: When a stellar iron core collapses, large numbers of neutrinos are formed, and then:

Answer: they immediately pass through the core and escape to space.