The solar mass (M☉) is a standard unit of mass in astronomy, equal to approximately 2×1030kg (20 nonillion kilograms in US short scale). It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. More precisely, the mass of the Sun is
nominal solar mass M☉ = 1.988416×1030 kg or a best estimate of M☉ = (1.988475±0.000092)×1030 kg.[2]