+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   103116 (1999 XD181) Classification: Main-belt Asteroid          SPK-ID: 2103116 [ 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 24 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2224337651813022 4.9472e-08   a 2.584274717604921 1.4724e-08 au q 2.009444761905212 1.2996e-07 au i 13.58900387733309 5.4427e-06 deg node 31.49811064382635 2.0992e-05 deg peri 298.164486432222 2.3312e-05 deg M 92.34077449609124 1.3219e-05 deg tp 2458811.277930777319 (2019-Nov-23.77793078) 5.3673e-05 TDB period 1517.422240443698 4.15 1.2968e-05 3.55e-08 d yr n .2372444468025822 2.0275e-09 deg/d Q 3.15910467330463 1.7999e-08 au   Orbit Determination Parameters    # obs. used (total)      1296      data-arc span      7765 days (21.26 yr)      first obs. used      1999-10-12      last obs. used      2021-01-14      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .46598      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 08:33:23   Additional Information  Earth MOID = 1.03842 au   Jupiter MOID = 2.36508 au   T_jup = 3.349  [ 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 14.88   n/a E2021B55   diameter diameter 3.953 km 0.219 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.163   0.008 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   103116 (1999 XD181)          Discovered 1999-Dec-12 by LINEAR at Socorro Reference: 20051019/Numbers.arc Last Updated: 2005-10-26 [ show close-approach data ] Alternate Designations  1999 XD181 = 2002 GS21  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-11 08:21 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin