The star Arietis has an apparent magnitude of +2.7 and a distance of 52 ly. What is its absolute magnitude?
A) +1.7
B) -0.9
C) +6.2
D) +3.7

Question

Quizplus · Accepted Answer

The absolute magnitude of a star is calculated using the formula: $M = m + 5 - 5 \log_{10}(d)$, where $M$ is the absolute magnitude, $m$ is the apparent magnitude, and $d$ is the distance in parsecs. Since 1 light year (ly) is approximately 0.306 parsecs, 52 ly is about 52 * 0.306 = 15.912 parsecs. Plugging these values into the formula gives $M = 2.7 + 5 - 5 \log_{10}(15.912)$, which approximately equals +1.7.

The Star Arietis Has an Apparent Magnitude of +2