Approximate heliocentric position and velocity of major planet
-2 = solution didn’
t converge.
-1 = illegal np (1-8)
0 = OK
+1 = warning: year outside 1000-3000
See SOFA/ERFA eraPlan94 for details
Note that Pluto is supported in SLA/F but not in this routine
Status -2 is equivalent to eraPlan94 status +2.
Note that velocity units here match the SLA/F documentation.