+ 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 2459396.5 (2021-Jul-01.0) TDB Reference: JPL 44 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .01452204015855325 1.1658e-08   a 3.214296604900424 1.4562e-08 au q 3.167618460522559 4.2715e-08 au i 21.96959370216912 5.8571e-07 deg node 44.18048636931466 1.0225e-06 deg peri 48.5956162046697 6.2962e-05 deg M 171.7168340608616 6.4415e-05 deg tp 2458392.490728619572 (2018-Sep-30.99072862) 0.00037561 TDB period 2104.880046698554 5.76 1.4304e-05 3.916e-08 d yr n .1710311238707641 1.1623e-09 deg/d Q 3.26097474927829 1.4774e-08 au   Orbit Determination Parameters    # obs. used (total)      2820      data-arc span      24346 days (66.66 yr)      first obs. used      1954-10-31      last obs. used      2021-06-27      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .40371      source      ORB      producer      Otto Matic      solution date      2021-Jul-08 12:51:37   Additional Information  Earth MOID = 2.1909 au   Jupiter MOID = 1.78797 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 10.86   n/a E2021B10   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 16.162 h n/a LCDB (Rev. 2020-October); 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.] [Behrend, R. (2020) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] 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 ] 2021-Jul-26 14:56 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin