Author Question: The energy source at the center of our galaxy is called a. Cygnus X-1. b. the Orion arm. c. the ... (Read 71 times)

frankwu · **on:** Jul 27, 2018

The energy source at the center of our galaxy is called

a. Cygnus X-1.
b. the Orion arm.
c. the Sun.
d. Sagittarius A.

Question 2

There is a main-sequence mass-luminosity relation because

a. helium fusion produces carbon.
b. stars expand when they become giants.
c. more massive stars support their larger weight by making more energy.
d. the helium flash occurs in degenerate matter.
e. all stars on the main sequence have about the same radius.