Astronomical Units

On astronomy scale distances are very large, hence comfortable units are:

Unit

Symbol

Value SI

parsec

pc{\rm pc}

3.0857×1016  m3.0857 \times 10^{16 } {\rm\; m}

megaparsec

Mpc{\rm Mpc}

3.0857×1022  m 3.0857 \times 10^{22} {\rm \;m}

lightyear

ly{\rm ly}

9.4605×1015  m9.4605 \times 10^{15} {\rm \;m}

astronomical unit

A.U.

1.496×1011  m1.496 \times 10^{11} {\rm \;m}

degree

^\circ

17.4532925  mrad17.4532925 {\rm \; mrad}

arcsecond

^{\prime\prime} (double prime)

0.0002777780.000277778^\circ

arcminute

^\prime (prime)

0.01666670.0166667^\circ

Constants

Name

Symbol

Value

Earth Radius

RR_{\oplus}

6.378×106  m6.378 \times 10^6 {\rm \; m}

Sun Radius

RR_\odot

6.961×108  m6.961 \times 10^8 {\; m}

Earth Mass

MM_\oplus

5.975×1024  kg5.975 \times 10^{24} {\rm \; kg}

Sun Mass

MM_\odot

1.989×1030  kg1.989 \times 10^{30} {\rm \; kg}

Sun Luminosity

SS_\odot

3.85×1026  W3.85 \times 10^{26} {\rm \; W}

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