+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   18870 (1999 US13) Classification: Main-belt Asteroid          SPK-ID: 2018870 [ 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 33 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1481639827117368 3.3828e-08   a 2.552344389022632 1.0769e-08 au q 2.174178879093084 8.6774e-08 au i 3.717306521016921 3.5568e-06 deg node 286.6599238882945 5.837e-05 deg peri 256.1053817703795 5.9942e-05 deg M 312.777681143996 1.543e-05 deg tp 2459591.867422015500 (2022-Jan-12.36742202) 6.425e-05 TDB period 1489.386240011752 4.08 9.4258e-06 2.581e-08 d yr n .2417103034315392 1.5297e-09 deg/d Q 2.93050989895218 1.2364e-08 au   Orbit Determination Parameters    # obs. used (total)      1783      data-arc span      16085 days (44.04 yr)      first obs. used      1977-03-26      last obs. used      2021-04-09      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .47328      source      ORB      producer      Otto Matic      solution date      2021-Jul-08 18:04:51   Additional Information  Earth MOID = 1.18116 au   Jupiter MOID = 2.05122 au   T_jup = 3.421  [ 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 13.96   n/a MPCxxxxx   diameter diameter 4.533 km 0.151 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.164   0.017 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   18870 (1999 US13)          Discovered 1999-Oct-29 by CSS at Catalina Reference: 20001111/Numbers.arc Last Updated: 2004-04-19 Alternate Designations  1999 US13 = 1977 FE2 = 1994 NG6 = 1997 HB  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Aug-02 00:38 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin