+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   21080 (1991 RD18) Classification: Main-belt Asteroid          SPK-ID: 2021080 [ 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 .04588548890828541 5.3412e-08   a 2.445867639556583 2.3045e-08 AU q 2.333637807110575 1.3727e-07 AU i 3.88581351616011 7.3591e-06 deg node 157.8241445561259 8.3866e-05 deg peri 108.7253098596684 0.00012554 deg M 311.3012045469721 9.0304e-05 deg tp 2456589.500769319033 (2013-Oct-24.00076932) 0.00034986 JED period 1397.165501156588 3.83 1.9746e-05 5.406e-08 d yr n .257664535591516 3.6416e-09 deg/d Q 2.558097472002591 2.4102e-08 AU   Orbit Determination Parameters    # obs. used (total)      887      data-arc span      7892 days (21.61 yr)      first obs. used      1991-09-13      last obs. used      2013-04-22      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      condition code      0      fit RMS      .553      data source      ORB      producer      Otto Matic      solution date      2013-Apr-29 14:28:33   Additional Information  Earth MOID = 1.32141 AU   T_jup = 3.494  [ 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 14.2 mag n/a PDS3 (MPO 8636)   21080 (1991 RD18)          Discovered 1991-Sep-13 by Holt, H. E. at Palomar (675) Reference: 20010208/Numbers.arc Last Updated: 2004-04-19 Alternate Designations  1991 RD18 = 1998 MO21 = 1999 UL14  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] 2013-May-23 16:06 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin