+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   18703 (1998 HN68) Classification: Outer Main-belt Asteroid          SPK-ID: 2018703 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 25 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1155273338798654 3.543e-08   a 3.209216976185282 2.0113e-08 au q 2.838464695084594 1.1767e-07 au i 3.279477004152758 3.7777e-06 deg node 271.7286600276412 8.5526e-05 deg peri 18.03562335100931 8.8573e-05 deg M 268.5374247978016 2.5452e-05 deg tp 2459734.004359447351 (2022-Jun-03.50435945) 0.00015067 TDB period 2099.892431155055 5.75 1.9741e-05 5.405e-08 d yr n .1714373530085922 1.6116e-09 deg/d Q 3.579969257285972 2.2436e-08 au   Orbit Determination Parameters    # obs. used (total)      1332      data-arc span      8829 days (24.17 yr)      first obs. used      1997-01-11      last obs. used      2021-03-15      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .56108      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 02:35:37   Additional Information  Earth MOID = 1.82045 au   Jupiter MOID = 1.57971 au   T_jup = 3.179  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 13.79   n/a E2021B10   diameter diameter 9.462 km 0.365 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.045   0.005 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   18703 (1998 HN68)          Discovered 1998-Apr-21 by LINEAR at Socorro Reference: 20001111/Numbers.arc Last Updated: 2004-04-19 [ show close-approach data ] Alternate Designations  1998 HN68 = 1997 EZ39  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-17 21:45 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin