The spiral galaxy in which we live is roughly 14 billion years old. For the stars that formed when the galaxy was very young (say, during the first billion years), which of the following statements is true? (See Table 19-1 of Universe, 11th ed.)

A)Some stars of half the mass of the Sun are still on the main sequence, but most have finished their lives as stars.
B)All stars of half the mass of the Sun are still on the main sequence.
C)Some stars of 15 times the mass of the Sun are still on the main sequence, but most have finished their lives as stars.
D)All stars of 3 times the mass of the Sun are still on the main sequence.

Question

The spiral galaxy in which we live is roughly 14 billion years old. For the stars that formed when the galaxy was very young (say, during the first billion years), which of the following statements is true? (See Table 19-1 of Universe, 11th ed.)
​
 ​
A)Some stars of half the mass of the Sun are still on the main sequence, but most have finished their lives as stars. 
B)All stars of half the mass of the Sun are still on the main sequence. 
C)Some stars of 15 times the mass of the Sun are still on the main sequence, but most have finished their lives as stars. 
D)All stars of 3 times the mass of the Sun are still on the main sequence.

Quizplus · Accepted Answer

The Answer of The spiral galaxy in which we live is roughly 14 billion years old. For the stars that formed when the galaxy was very young (say, during the first billion years), which of the following statements is true? (See Table 19-1 of Universe, 11th ed.)
​
 ​
A)Some stars of half the mass of the Sun are still on the main sequence, but most have finished their lives as stars. 
B)All stars of half the mass of the Sun are still on the main sequence. 
C)Some stars of 15 times the mass of the Sun are still on the main sequence, but most have finished their lives as stars. 
D)All stars of 3 times the mass of the Sun are still on the main sequence.

The Spiral Galaxy in Which We Live Is Roughly 14