+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   8281 (1991 PC18) Classification: Main-belt Asteroid          SPK-ID: 2008281 [ 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 .07915335075176287 6.4274e-08   a 2.805989968238268 2.5672e-08 AU q 2.583886460076376 1.7579e-07 AU i 6.182410354333602 7.2531e-06 deg node 295.8375882077801 6.9093e-05 deg peri 122.6607545023864 8.9465e-05 deg M 146.3157803626147 5.4735e-05 deg tp 2455702.723618783300 (2011-May-21.22361878) 0.00025945 JED period 1716.831203137924 4.70 2.3561e-05 6.451e-08 d yr n .2096886399443422 2.8777e-09 deg/d Q 3.028093476400159 2.7704e-08 AU   Orbit Determination Parameters    # obs. used (total)      955      data-arc span      21798 days (59.68 yr)      first obs. used      1953-08-15      last obs. used      2013-04-20      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      condition code      0      fit RMS      .56304      data source      ORB      producer      Otto Matic      solution date      2013-Apr-29 13:30:30   Additional Information  Earth MOID = 1.60222 AU   T_jup = 3.310  [ 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 13.0 mag n/a PDS3 (MPC 31214)   8281 (1991 PC18)          Discovered 1991-Aug-08 by Holt, H. E. at Palomar (675) Reference: DISCOVERY.DB Last Updated: 2003-08-29 Alternate Designations  1991 PC18 = 1993 BX  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] 2013-May-24 06:31 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin