Which event marks the beginning of a supernova?
A. the sudden collapse of an iron core into a compact ball of neutrons
B. the onset of helium burning after a helium flash
C. the beginning of neon burning in an extremely massive star
D. the sudden initiation of the CNO cycle
Answer:A
Which event marks the beginning of a supernova?
A. the sudden collapse of an iron core into a compact ball of neutrons B. the onset of helium burning after a helium flash C. the beginning of neon burning in an extremely massive star D. the sudden initiation of the CNO cycle