+ 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 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 45 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1256543179640169 2.0985e-08   a 2.587649177850133 1.0144e-08 au q 2.262499885277225 5.5506e-08 au i 13.46604503464285 8.6535e-07 deg node 192.6740643435144 4.2259e-06 deg peri 33.10532260719034 6.4897e-06 deg M 207.5020229265395 6.5391e-06 deg tp 2459844.547803099810 (2022-Sep-22.04780310) 3.0468e-05 TDB period 1520.395309927572 4.16 8.9402e-06 2.448e-08 d yr n .2367805252024551 1.3923e-09 deg/d Q 2.912798470423041 1.1418e-08 au   Orbit Determination Parameters    # obs. used (total)      2566      data-arc span      11102 days (30.40 yr)      first obs. used      1990-10-11      last obs. used      2021-03-04      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .43812      source      ORB      producer      Otto Matic      solution date      2021-Mar-17 03:04:52   Additional Information  Earth MOID = 1.26566 au   Jupiter MOID = 2.07351 au   T_jup = 3.372  [ 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 13.46   n/a E2021B10   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-Apr-13 05:57 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin