+ 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 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 49 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .3091282831010794 2.7351e-08   a 2.926698949445004 9.4194e-09 au q 2.021973528049337 7.988e-08 au i 26.19044941350894 4.1132e-06 deg node 150.094252962419 7.8057e-06 deg peri 264.385260279582 1.113e-05 deg M 180.6633317530211 9.9442e-06 deg tp 2460111.528788095168 (2023-Jun-16.02878810) 5.3248e-05 TDB period 1828.79701580374 5.01 8.8288e-06 2.417e-08 d yr n .1968507149175237 9.5033e-10 deg/d Q 3.831424370840671 1.2331e-08 au   Orbit Determination Parameters    # obs. used (total)      3004      data-arc span      29915 days (81.90 yr)      first obs. used      1939-02-21      last obs. used      2021-01-16      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .42313      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 19:04:41   Additional Information  Earth MOID = 1.20528 au   Jupiter MOID = 2.26351 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 10.37   n/a E2021B10 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. 2020-October); Warner et al., 2009 Published Reference List: [Polakis, T. (2019) Minor Planet Bull. 46, 287-292.] [Pal, A.; Szakats, R.; Kiss, C.; Bodi, A.; et al. (2019) Ap. J. Supl. Ser. 247, id.26.] 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 ] 2021-Mar-06 11:55 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin