MASS OF M 31

Spectrographic rotation 3.5×10^9 ☉

Öpik’s method 1.6×10^9

The distance of N.G.C. 4594 is unknown, but the assumption that it is a

normal nebula with an absolute magnitude of –15.2 places it at 700,000

parsecs. The orders of the mass by the two methods are then

Extra-galactic nebulae · 第 27 / 40 题