Author Question: In the collapsing cloud fragment stage (stage 2 ) of star formation, the size of the cloud fragment ... (Read 40 times)

fasfsadfdsfa · **on:** Jul 27, 2018

In the collapsing cloud fragment stage (stage 2 ) of star formation, the size of the cloud fragment is about:

A) the size of the solar system.
B) 10 times the size of the solar system.
C) 100 times the size of the solar system.
D) 1,000 times the size of the solar system.
E) 10,000 times the size of the solar system.

Question 2

When does a protostar become a true star?

A) when the star is 1 million years old
B) when the central temperature reaches 1 million Kelvin
C) when nuclear fusion begins in the core
D) when the thermal energy becomes trapped in the center
E) when the stellar winds and jets blow away the surrounding material