+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   100839 (1998 HW18) Classification: Main-belt Asteroid          SPK-ID: 2100839 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 17 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1844551026595463 5.926e-08   a 2.275210990277364 1.2257e-08 au q 1.855536713493624 1.3947e-07 au i 5.414418198348772 5.2211e-06 deg node 207.3378516252292 5.586e-05 deg peri 310.1701274782882 5.7218e-05 deg M 188.4682384804305 1.381e-05 deg tp 2459597.773146173883 (2022-Jan-18.27314617) 5.0575e-05 TDB period 1253.519060947015 3.43 1.013e-05 2.773e-08 d yr n .2871914845299802 2.3208e-09 deg/d Q 2.694885267061103 1.4518e-08 au   Orbit Determination Parameters    # obs. used (total)      401      data-arc span      7248 days (19.84 yr)      first obs. used      1998-03-22      last obs. used      2018-01-24      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .65617      source      ORB      producer      Otto Matic      solution date      2018-Feb-05 23:12:36   Additional Information  Earth MOID = .869742 au   Jupiter MOID = 2.30923 au   T_jup = 3.581  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 16.7   n/a MPO320188   100839 (1998 HW18)          Discovered 1998-Apr-18 by LINEAR at Socorro Reference: 20051019/Numbers.arc Last Updated: 2005-10-26 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2020-Oct-19 15:52 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin