+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   (2001 HL31) Classification: Apollo [NEO, PHA]          SPK-ID: 3076784 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2452031.5 (2001-May-02.0) TDB Reference: JPL 17 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .778728816205939 0.0078383   a 2.436045069717438 0.076598 au q .5390265763520632 0.0021455 au i 12.85937082268816 0.15061 deg node 38.364214253 0.033564 deg peri 286.8561696305793 0.088372 deg M 345.7461672686688 0.74048 deg tp 2452086.486434895406 (2001-Jun-25.98643490) 0.26305 TDB period 1388.757461621864 3.80 65.501 0.1793 d yr n .2592245298034784 0.012226 deg/d Q 4.333063563082812 0.13625 au   Orbit Determination Parameters    # obs. used (total)      72      data-arc span      9 days      first obs. used      2001-04-29      last obs. used      2001-05-08      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      9      norm. resid. RMS      .33284      source      ORB      producer      Otto Matic      solution date      2017-Apr-06 09:16:22   Additional Information  Earth MOID = .049671 au   Jupiter MOID = 1.40494 au   T_jup = 2.973  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 20.3   n/a MPO13855   [ show close-approach data ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] 2021-Jan-18 17:06 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin