+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   21865 (1999 TD246) Classification: Main-belt Asteroid          SPK-ID: 2021865 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459396.5 (2021-Jul-01.0) TDB Reference: JPL 47 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1254878619606687 2.0965e-08   a 2.588075765167204 1.0155e-08 au q 2.26330367080415 5.5473e-08 au i 13.46551749895515 8.6524e-07 deg node 192.6666124258617 4.2256e-06 deg peri 33.07054215580985 6.4912e-06 deg M 253.941052804687 6.7437e-06 deg tp 2459844.531672927505 (2022-Sep-22.03167293) 3.0495e-05 TDB period 1520.771292938404 4.16 8.9511e-06 2.451e-08 d yr n .2367219855290766 1.3933e-09 deg/d Q 2.912847859530258 1.143e-08 au   Orbit Determination Parameters    # obs. used (total)      2580      data-arc span      11133 days (30.48 yr)      first obs. used      1990-10-11      last obs. used      2021-04-04      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .44605      source      ORB      producer      Otto Matic      solution date      2021-Jul-08 18:37:16   Additional Information  Earth MOID = 1.26806 au   Jupiter MOID = 2.07226 au   T_jup = 3.371  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 13.47   n/a MPCxxxxx   diameter diameter 5.170 km 0.071 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.321   0.027 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   21865 (1999 TD246)          Discovered 1999-Oct-08 by CSS at Catalina Reference: 20010208/Numbers.arc Last Updated: 2004-04-19 Alternate Designations  1999 TD246 = 1990 TP16 = 1993 FV25 = 1997 HW4 = 1998 QB64  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Jul-27 04:01 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin