### 44.2 Astronomy and Astrophysics

`GSL_CONST_MKSA_ASTRONOMICAL_UNIT`

  The length of 1 astronomical unit (mean earth-sun distance), au.

`GSL_CONST_MKSA_GRAVITATIONAL_CONSTANT`

  The gravitational constant, G.

`GSL_CONST_MKSA_LIGHT_YEAR`

  The distance of 1 light-year, ly.

`GSL_CONST_MKSA_PARSEC`

  The distance of 1 parsec, pc.

`GSL_CONST_MKSA_GRAV_ACCEL`

  The standard gravitational acceleration on Earth, g.

`GSL_CONST_MKSA_SOLAR_MASS`

  The mass of the Sun.