Multiple Choice
What ionizes the gas in a planetary nebula and makes it visible?
A) X-ray photons emitted by a pulsar
B) Ultraviolet photons emitted by a white dwarf
C) The shock wave from a supernova
D) Hydrogen burning in the nebular gas
Correct Answer:

Verified
Correct Answer:
Verified
Related Questions
Q1: The percent of hydrogen in the Sun's
Q2: In a white dwarf,what is the source
Q4: If a <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB4068/.jpg" alt="If a
Q4: Pressure from degenerate electrons keeps the core
Q6: One star in a binary will almost
Q8: A Type I supernova has a luminosity
Q10: A star's surface temperature during the horizontal
Q11: The luminosity of a star depends on<br>A)
Q17: The Sun eventually could become a nova.
Q84: Why does the core of a main-sequence