# Introduction to Astrophysics/Astronomical Constants

Speed of light: *c* = 2.99792458 × 10^{8} m s^{-1}

Gravitation Constant: *G* = 6.6742(10) × 10^{-11} m^{3} kg^{-1}s^{-2}

Mass of Sun: *M _{sun}* = 1.99 × 10

^{30}kg

Luminosity of Sun:

*L*= 3.83 × 10

_{sun}^{26}J s

^{-1}

Radius of Sun:

*R*= 6.96 × 10

_{sun}^{8}m

1 astronomical unit (AU): 1.496 × 10

^{11}m

1 light year (ly): 9.461 × 10

^{15}m = 0.307 pc

1 parsec (pc): 3.086 × 10

^{16}m = 3.26 ly

Solar effective temperature:

*T*

_{eff}= 5777 K

Hubble Constant:

*H*

_{0}= 70.1±1.3 kms

^{-1}Mpc

^{-1}

Cosmological Constant: |Λ|≤10

^{-51}m

^{-2}

Cosmic background radiation = 2.725(1) K

Mass of Earth:

*M*= 5.97370(76) × 10

_{e}^{24}kg

Radius of Earth:

*R*= 6.378136 × 10

_{e}^{6}m