Which is NOT needed to compute a distance to a star by the spectroscopic parallax method?
A) the mathematical relationship among distance, absolute magnitude, and apparent magnitude
B) the star's stellar parallax
C) the star's apparent magnitude
D) the star's luminosity

Question

Quizplus · Accepted Answer

The spectroscopic parallax method does not use the star's stellar parallax, which is the apparent shift in its position due to the Earth's orbit around the Sun. Instead, it relies on the mathematical relationship among distance, absolute magnitude, apparent magnitude, and the star's luminosity inferred from its spectrum. The apparent magnitude and the spectrum (from which one can determine the star's luminosity class) are used to calculate the absolute magnitude of the star, and then the distance can be derived from the difference between the apparent magnitude and the absolute magnitude.

Which Is NOT Needed to Compute a Distance to a Star