In Figure 1C, which star is bigger?

What can we conclude about the relative properties of stars B and D?

In Figure 1A, which star is hotter?

The image below shows the motion of several distance stars relative to an observer. The arrows indicate the star’s direction of motion, and the longer the arrow, the faster a star’s motion. Rank these stars in order from the greatest “blueshift” to the greatest “redshift”. Note: If a star would exhibit no shift, then it should go between those with blueshift and those with redshift.

The Schwartzschild radius for a 10 solar mass star is

The figure below is referred to as the

The Chandrasekhar mass limit for a white dwarf is:

Regarding the three stars in the comparison above, which star is intrinsically the brightest. Comparing the Relative Brightness of Three Stars Star Absolute Apparent A 2.3 1.2 B -1.5 3.4 C 2.6 2.6  

A tightly wound, barred spiral galaxy would, in Hubble’s system, be:

What happens when an interstellar cloud fragment shrinks?