The physical process believed to provide the energy for the ejection of a planetary nebula from a star is
A) transfer of hydrogen-rich material to the surface of a white dwarf from its companion in a binary star system.
B) a series of thermal pulses in a helium-burning shell.
C) a collision with another star.
D) core collapse and the ensuing shock wave.

Question

Quizplus · Accepted Answer

A series of thermal pulses in a helium-burning shell is the physical process that is believed to provide the energy for the ejection of a planetary nebula from a star. During these pulses, outer layers of the star are pushed outward and shed, creating a shell that eventually forms a planetary nebula. Choice A describes a process that can lead to nova explosions but not planetary nebulae. Choice C involves a collision between stars, which can also create novae or supernovae but is not a required process for the creation of planetary nebulae. Choice D describes the physical process that leads to the creation of supernovae.

The Physical Process Believed to Provide the Energy for the Ejection