+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   1838 Ursa (1971 UC) Classification: Outer Main-belt Asteroid          SPK-ID: 2001838 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 37 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .01470903502330679 3.3661e-08   a 3.214418688111123 1.5917e-08 au q 3.167137691048124 1.0612e-07 au i 21.96929146156549 4.264e-06 deg node 44.18286978384593 1.0008e-05 deg peri 49.69517359287305 0.00016427 deg M 102.8504449868156 0.00016228 deg tp 2458399.110601934399 (2018-Oct-07.61060193) 0.00094905 TDB period 2104.999967004219 5.76 1.5635e-05 4.281e-08 d yr n .1710213803529615 1.2703e-09 deg/d Q 3.261699685174121 1.6151e-08 au   Orbit Determination Parameters    # obs. used (total)      2694      data-arc span      24018 days (65.76 yr)      first obs. used      1954-10-31      last obs. used      2020-08-03      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .39334      source      ORB      producer      Otto Matic      solution date      2020-Aug-24 22:41:35   Additional Information  Earth MOID = 2.19166 au   Jupiter MOID = 1.78971 au   T_jup = 3.076  [ 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 10.8   n/a MPO263361   diameter diameter 40.054 km 0.380 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 16.141 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List: [Gross, J. (2003) Minor Planet Bull. 30, 44-46.] [Hanus, J.; Broz, M.; Durech, J.; Warner, B.D.; et al. (2013) Astron. Astrophys. 559, A134.] [Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.] [Durech, J.; Hanus, J.; Oszkiewsicz, D.; Vanco, R. (2016) Astron. Astrophys. 587, A48.] [Hanus, J.; Durech, J.; Oszkiewicz, D.A.; Behrend, R.; et al. (2016) Astron. Astrophys. 586, A108.] geometric albedo albedo 0.057   0.011 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   1838 Ursa (1971 UC)          Discovered 1971-Oct-20 by Wild, P. at Zimmerwald Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  1971 UC = 1951 GB1 = 1954 UA = 1965 UE = 1977 UP1  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2020-Sep-24 02:34 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin