+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   21691 (1999 RC42) Classification: Main-belt Asteroid          SPK-ID: 2021691 [ 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 38 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .08394037644339503 2.1513e-08   a 2.429902018853065 8.0177e-09 au q 2.225935128669973 5.1902e-08 au i 4.822573087294464 6.5885e-07 deg node 332.6551652539384 5.1752e-06 deg peri 33.77660453446272 1.2185e-05 deg M 215.9391776320533 1.2024e-05 deg tp 2459754.136811118460 (2022-Jun-23.63681112) 4.7184e-05 TDB period 1383.507665210937 3.79 6.8475e-06 1.875e-08 d yr n .260208171629546 1.2879e-09 deg/d Q 2.633868909036157 8.6907e-09 au   Orbit Determination Parameters    # obs. used (total)      2284      data-arc span      9083 days (24.87 yr)      first obs. used      1995-08-01      last obs. used      2020-06-13      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .43912      source      ORB      producer      Otto Matic      solution date      2021-Mar-17 03:03:09   Additional Information  Earth MOID = 1.22383 au   Jupiter MOID = 2.73858 au   T_jup = 3.498  [ 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 14.07   n/a E2021B10   diameter diameter 3.207 km 0.251 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.359   0.054 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   21691 (1999 RC42)          Discovered 1999-Sep-13 by Korlevic, K. at Visnjan Reference: 20010208/Numbers.arc Last Updated: 2004-04-19 [ show close-approach data ] Alternate Designations  1999 RC42 = 1998 KU17  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-10 12:09 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin