Astronomers arrange the stars into groups called spectral classes (or types) according to the kinds of lines they find in their spectra. These spectral classes are arranged in order of:
A) decreasing surface temperature
B) increasing mass
C) increasing amount of hydrogen
D) decreasing distance from us
E) you can't fool me, there is no order to the spectral types (that's why the letters are not in alphabetical order)

Question

Quizplus · Accepted Answer

Spectral classes are arranged in order of decreasing surface temperature, with the hottest stars being classified as O-type and the coolest stars being classified as M-type. The spectral lines present in a star's spectrum provide information about its temperature, composition, and other physical properties. Therefore, by grouping stars with similar spectra, astronomers can infer their properties and classify them into spectral classes.

Astronomers Arrange the Stars into Groups Called Spectral Classes (Or