How did astronomers discover the relationship between spectral type and mass for main sequence stars?
A) by measuring stellar radii with very powerful optical telescopes
B) by measuring stellar radii with very powerful radio telescopes
C) by comparing stars with the same spectral type but different luminosities
D) by using computer models of hydrogen fusion and stellar structure
E) by measuring the masses and spectral types of main-sequence stars in binary systems

Question

Quizplus · Accepted Answer

Astronomers discovered the relationship between spectral type and mass for main sequence stars primarily by studying stars in binary systems. In such systems, the gravitational interaction between the two stars allows for the determination of their masses. By observing many binary systems and noting the spectral type of each star, astronomers were able to correlate spectral type with mass. This method is effective because the mass of a star in a binary system can be determined from the orbital motion of the stars around their common center of mass, independent of the stars' distances from Earth.

How Did Astronomers Discover the Relationship Between Spectral Type and Mass