+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   22946 (1999 TH218) Classification: Main-belt Asteroid          SPK-ID: 2022946 [ 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 20 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1553973007575433 3.7023e-08   a 3.162896261809761 2.2562e-08 au q 2.6713907201484 1.2088e-07 au i 10.0441751202621 3.5789e-06 deg node 201.1705759297704 2.3818e-05 deg peri 276.3130820207314 2.6827e-05 deg M 218.9073280215685 1.5801e-05 deg tp 2460005.744572238905 (2023-Mar-02.24457224) 9.543e-05 TDB period 2054.593211264157 5.63 2.1984e-05 6.019e-08 d yr n .1752171661165462 1.8748e-09 deg/d Q 3.654401803471122 2.6068e-08 au   Orbit Determination Parameters    # obs. used (total)      892      data-arc span      9871 days (27.03 yr)      first obs. used      1993-10-10      last obs. used      2020-10-19      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .52895      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 04:15:01   Additional Information  Earth MOID = 1.7108 au   Jupiter MOID = 1.59928 au   T_jup = 3.162  [ 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 14.3   n/a MPO435914   diameter diameter 8.305 km 0.268 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.064   0.013 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   22946 (1999 TH218)          Discovered 1999-Oct-15 by LINEAR at Socorro Reference: 20010309/Numbers.arc Last Updated: 2004-04-19 [ show close-approach data ] Alternate Designations  1999 TH218 = 1996 JW6  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-23 02:16 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin