Astronomical Unit of Mass
The astronomical unit of mass is the solar mass. The symbol S is often used in astronomy to refer to this unit, although M☉ is also common. The solar mass (M⊙), 1.98892×1030 kg, is a standard way to express mass in astronomy, used to describe the masses of other stars and galaxies. It is equal to the mass of the Sun, about 333,000 times the mass of the Earth or 1,048 times the mass of Jupiter.
In practice, the masses of celestial bodies appear in the dynamics of the solar system only through the products GM, where G is the constant of gravitation. In the past, GM of the sun could be determined experimentally with only limited accuracy. Its present accepted value is GM☉=1.327 124 420 99 × 1020±1010 m3s−2
Read more about this topic: Astronomical System Of Units
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