Sirius is a star with spectral type A and Rigel is a star with spectral type B. What can we conclude?
A) Sirius has a higher core temperature than Rigel.
B) Sirius has a higher surface temperature than Rigel.
C) Rigel has a higher surface temperature than Sirius.
D) Rigel has a higher core temperature than Sirius.
Question 2
As with stars, binary galaxy pairs are useful in finding their total mass.
Indicate whether the statement is true or false