•Question 6 (1 point) You observe two
stars with the same
absolute magnitude and determine spectroscopically
that one is type B star while the other is a type G star. What can you conclude about the
sizes of the stars?
a.Nothing.
•b.The G star is larger than the B star.
•c.The B star is larger than the G star.
•d.The stars are the same size.
•L
is equal for the two stars, so (TG/TB)4(RG/RB)2 must equal one. The temperature of the G star is cooler
than that of a
B star, so the first term must be less than one. There for the other term must be greater
than one. This is also clear from looking at lines
of constant radius
on an HR diagram, that a G star would have to be a giant to have as much luminosity as a
B star.