+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   1585 Union (1947 RG) Classification: Main-belt Asteroid          SPK-ID: 2001585 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 48 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .3090488635681853 2.7353e-08   a 2.926988249531072 9.4476e-09 au q 2.022405857336062 7.9892e-08 au i 26.19014330843669 4.1247e-06 deg node 150.0927065629226 7.8053e-06 deg peri 264.4148752933093 1.1143e-05 deg M 141.249066165 9.8426e-06 deg tp 2458282.849519787917 (2018-Jun-13.34951979) 4.8088e-05 TDB period 1829.068183534423 5.01 8.8557e-06 2.425e-08 d yr n .1968215308979622 9.5294e-10 deg/d Q 3.831570641726081 1.2367e-08 au   Orbit Determination Parameters    # obs. used (total)      2969      data-arc span      29782 days (81.54 yr)      first obs. used      1939-02-21      last obs. used      2020-09-05      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .42428      source      ORB      producer      Otto Matic      solution date      2020-Nov-13 04:17:29   Additional Information  Earth MOID = 1.20656 au   Jupiter MOID = 2.26291 au   T_jup = 3.058  [ 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 10.4   n/a MPO473785 IRAS observations used: 6 diameter diameter 55.271 km 0.243 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 12.798 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List: [Polakis, T. (2019) Minor Planet Bull. 46, 287-292.] geometric albedo albedo 0.031   0.004 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   B-V BV 0.590   0.020 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=8.56 deg. U-B UB 0.290   0.030 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=8.56 deg. 1585 Union (1947 RG)          Discovered 1947-Sep-07 by Johnson, E. L. at Johannesburg (UO) Reference: DISCOVERY.DB Last Updated: 2003-08-29 Alternate Designations  1947 RG = 1929 DB = 1937 QF = 1939 CD1 = 1944 DG = 1949 EE = 1952 QA1 = 1952 SD  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2020-Nov-27 07:28 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin