+ 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 | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 31 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1482124434527043 3.3869e-08   a 2.551986599718113 1.0743e-08 au q 2.173750430115333 8.6872e-08 au i 3.717608594644654 3.5571e-06 deg node 286.6591364651976 5.8409e-05 deg peri 256.166640957738 5.9979e-05 deg M 265.3450946793333 1.5338e-05 deg tp 2459592.022419586320 (2022-Jan-12.52241959) 6.4245e-05 TDB period 1489.073076282515 4.08 9.4024e-06 2.574e-08 d yr n .2417611370012433 1.5265e-09 deg/d Q 2.930222769320893 1.2335e-08 au   Orbit Determination Parameters    # obs. used (total)      1775      data-arc span      16052 days (43.95 yr)      first obs. used      1977-03-26      last obs. used      2021-03-07      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .47398      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 02:40:25   Additional Information  Earth MOID = 1.17941 au   Jupiter MOID = 2.05234 au   T_jup = 3.421  [ 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 13.95   n/a E2021B10   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 [ show close-approach data ] Alternate Designations  1999 US13 = 1977 FE2 = 1994 NG6 = 1997 HB  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-14 06:10 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin