What is spectroscopic parallax?
A) an apparent change in position of the absorption lines in a star's spectrum due to the Doppler shift caused by Earth's motion around the Sun
B) an apparent change in position of a nearby star compared with distant background stars due to the motion of Earth around the Sun
C) a change in position of the absorption lines in a star's spectrum due to the Doppler shift caused by the star's motion around the center of mass in a binary star system
D) the distance to a star measured using the spectral luminosity class of the star and the inverse square law

Question

Quizplus · Accepted Answer

Spectroscopic parallax is a method of determining the distance to a star using its spectral luminosity class (which indicates its intrinsic brightness) and the inverse square law (which relates distance to apparent brightness). By comparing the apparent brightness of a star to its intrinsic brightness, the distance can be determined, hence spectroscopic parallax is often used to measure the distances of stars that are too far away for traditional parallax measurements.

What Is Spectroscopic Parallax