# Common units in astronomy, astrophysics, and space science

**Astronomical Unit (AU):** A distance unit equal to the average distance from the Earth to the Sun. In SI units, it is 1.50·10^{11} m.

**Solar Mass (M _{Sun}):** A mass unit equal to the mass of the Sun. In SI units, it is 1.99·10

^{30}kg.

**Earth Mass (M _{Earth}):** A mass unit equal to the mass of the Earth. In SI units, it is 5.97·10

^{24}kg.

**Jupiter Mass (M _{J}):** A mass unit equal to the mass of Jupiter. In SI units, it is 1.90·10

^{27}kg.

**Day (d):** A time unit equal to the time it takes for a planet to complete one revolution around its axis. If no other information is provided, the planet in question is assumed to be Earth.

**Year (yr):** A time unit equal to the time it takes for a planet to complete one orbit. If no other information is provided, the planet in question is assumed to be Earth.