+ 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 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 20 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1845922788486226 5.8406e-08   a 2.275069618974626 1.1509e-08 au q 1.855109333468832 1.3742e-07 au i 5.41470596761096 5.1648e-06 deg node 207.3362792892479 4.8478e-05 deg peri 310.1502328648572 4.9781e-05 deg M 245.9475795975287 1.3853e-05 deg tp 2459597.593217102983 (2022-Jan-18.09321710) 5.0066e-05 TDB period 1253.402230769111 3.43 9.5106e-06 2.604e-08 d yr n .2872182537756434 2.1794e-09 deg/d Q 2.695029904480419 1.3633e-08 au   Orbit Determination Parameters    # obs. used (total)      453      data-arc span      8325 days (22.79 yr)      first obs. used      1998-03-22      last obs. used      2021-01-05      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .62389      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 19:33:02   Additional Information  Earth MOID = .869091 au   Jupiter MOID = 2.30826 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 16.64   n/a E2021B55   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 ] 2021-Feb-28 17:08 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin