+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   55754 (1991 RP18) Classification: Main-belt Asteroid          SPK-ID: 2055754 [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2456400.5 (2013-Apr-18.0) TDB Reference: JPL 1 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1965063559346707 7.0522e-08   a 2.240021241926423 1.446e-08 AU q 1.799842830459207 1.5987e-07 AU i 1.234694536969301 8.2984e-06 deg node 317.7851899184314 0.00026374 deg peri 39.7112950793534 0.00026415 deg M 153.9855857170886 1.926e-05 deg tp 2455876.713620955168 (2011-Nov-11.21362096) 6.3433e-05 JED period 1224.550308251441 3.35 1.1857e-05 3.246e-08 d yr n .293985471706794 2.8467e-09 deg/d Q 2.68019965339364 1.7302e-08 AU   Orbit Determination Parameters    # obs. used (total)      443      data-arc span      7871 days (21.55 yr)      first obs. used      1991-09-13      last obs. used      2013-04-01      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      condition code      0      fit RMS      .58937      data source      ORB      producer      Otto Matic      solution date      2013-Apr-29 16:31:55   Additional Information  Earth MOID = .795483 AU   T_jup = 3.609  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 15.961 mag .45901 1 autocmod 2.5c 55754 (1991 RP18)          Discovered 1991-Sep-13 by Holt, H. E. at Palomar (675) Reference: 20030318/Numbers.arc Last Updated: 2004-04-19 Alternate Designations  1991 RP18 = 1997 HX13 = 2000 GE12  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] 2013-May-24 04:26 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin