[Visit the USGS Home Page]

Astrogeology Research Program


IAU/IAG Working Group (WG) on Cartographic Coordinates and Rotational Elements

Rotation and pole position for the Sun and planets

Tables: I - II - III - IV - V - VI
TABLE I
Recommended values for the direction of the north pole of rotation and the prime meridian of the Sun and planets (2000)

The standard epoch is 2000 January 1.5, that is, JD 2451545.0 TT

Sun α0 = 286°.13  
  δ0 = 63°.87  
  W = 84°.10+14°.1844000d  

Mercury α0 = 281.01-0.033T  
  δ0 = 61.45-0.005T  
  W = 329.548+6.1385025d (a)

Venus α0 = 272.76  
  δ0 = 67.16  
  W = 160.20-1.4813688d (b)

Earth α0 = 0.00-0.641T  
  δ0 = 90.00-0.557T  
  W = 190.147+360.9856235d  

Mars α0 = 317.68143-0.1061T  
  δ0 = 52.88650-0.0609T  
  W = 176.630+350.89198226d (c)

Jupiter α0 = 268.05-0.009T  
  δ0 = 64.49+0.003T  
  W = 284.95+870.5366420d (d)

Saturn α0 = 40.589-0.036T  
  δ0 = 83.537-0.004T  
  W = 38.90+810.7939024d (d)

Uranus α0 = 257.311  
  δ0 = -15.175  
  W = 203.81-501.1600928d (d)

Neptune α0 = 299.36+0.70 sin N  
  δ0 = 43.46-0.51 cos N  
  W = 253.18+536.3128492d -0.48 sin N (d)
  N = 357.85+52.316T  

Pluto α0 = 313.02  
  δ0 = 9.09  
  W = 236.77-56.3623195d (e)

α0, δ0: Are standard equatorial coordinates with equinox J2000 at epoch J2000.
Approximate coordinates of the north pole of the invariable plane are α0=273°.85, δ0=66°.99.
T: Interval in Julian centuries (of 36525 days) from the standard epoch.
d: Interval in days from the standard epoch.
(a): The 20° meridian is defined by the crater Hun Kal.
(b): The 0° meridian is defined by the central peak in the crater Ariadne.
(c): The 0° meridian is defined by the crater Airy-0.
(d): The equations for W for Jupiter, Saturn, Uranus and Neptune refer to the rotation of their magnetic fields (System III). On Jupiter, System I (WI= 67°.1 + 877°.900d) refers to the mean atmospheric equatorial rotation; System II (WII= 43°.3 + 870°.270d) refers to the mean atmospheric rotation north of the south component of the north equatorial belt, and south of the north component of the south equatorial belt.
(e): The 0° meridian is defined as the mean sub-Charon meridian.