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Astronomical unit per year (AU/yr) is a unit of velocity used in astronomy to denote the orbital motion of planets, asteroids, and close binaries around the star. This unit shall be useful especially for planets because units in this derivative are based on our homeworld in unity. Another reason is that this unit is calculated most simply, easier than calculating orbital velocity in km/s, mi/s, kph or mph.

1 AU/yr is the orbital velocity of Earth divided by 2π, 4.756 km/s or 2.955 mi/s (17120 kph or 10640 mph), about the velocity of Pluto. To calculate the orbital velocity, simply divide semimajor axis in astronomical units by orbital period in years and then multiply the quotient 2π.

Object Semimajor axis Period Velocity
2M1207b 40.641 AU 1623.866 yr 0.153 AU/yr
Sedna 518.568 AU 11398.250 yr 0.286 AU/yr
Eris 68.009 AU 560.900 yr 0.762 AU/yr
Fomalhaut b 113.516 AU 872.152 yr 0.816 AU/yr
Pluto 39.264 AU 247.681 yr 0.996 AU/yr
Neptune 30.058 AU 164.791 yr 1.146 AU/yr
Uranus 19.229 AU 84.323 yr 1.432 AU/yr
PSR B1620-26 b 23.251 AU 96.413 yr 1.514 AU/yr
Saturn 9.538 AU 29.457 yr 2.033 AU/yr
Jupiter 5.200 AU 11.859 yr 2.754 AU/yr
Ceres 2.765 AU 4.601 yr 3.778 AU/yr
Mars 1.524 AU 1.881 yr 5.082 AU/yr
Earth 1.000 AU 1.000 yr 6.283 AU/yr
Venus 0.723 AU 0.615 yr 7.388 AU/yr
Mercury 0.387 AU 0.241 yr 10.020 AU/yr
Proxima Centauri b 0.050 AU 0.031 yr 10.324 AU/yr
51 Pegasi b 0.053 AU 0.012 yr 28.757 AU/yr
PSR J1719-1438 b 4.452E-3 AU 2.4834E-4 yr 112.627 AU/yr
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