+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   1845 Helewalda (1972 UC) Classification: Main-belt Asteroid          SPK-ID: 2001845 [ 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 40 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .05628952598943292 3.3203e-08   a 2.96861754841961 1.1827e-08 au q 2.801515473775158 9.8662e-08 au i 10.72021667595449 3.9361e-06 deg node 142.5892218138021 1.6814e-05 deg peri 324.1489353617184 3.6649e-05 deg M 82.25439979539878 3.13e-05 deg tp 2458773.639037452017 (2019-Oct-17.13903745) 0.00016276 TDB period 1868.227680215474 5.11 1.1164e-05 3.057e-08 d yr n .192695999428977 1.1515e-09 deg/d Q 3.135719623064062 1.2492e-08 au   Orbit Determination Parameters    # obs. used (total)      3146      data-arc span      32639 days (89.36 yr)      first obs. used      1931-11-04      last obs. used      2021-03-15      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .39796      source      ORB      producer      Otto Matic      solution date      2021-Apr-12 13:01:17   Additional Information  Earth MOID = 1.82495 au   Jupiter MOID = 1.92897 au   T_jup = 3.235  [ 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 11.31   n/a E2021B10   diameter diameter 19.930 km 0.377 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 7.2786 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Carbo, L.; Green, D.; Kragh, K.; Krotz, J.; et al. (2009) Minor Planet Bull. 36, 152-157.] [Behrend, R. (2010) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Brinsfield, J.W. (2010) Minor Planet Bull. 37, 146-147.] [Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.] [DeGraff, D.R. (2017) Minor Planet Bull. 44, 350-354.] geometric albedo albedo 0.134   0.014 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   1845 Helewalda (1972 UC)          Discovered 1972-Oct-30 by Wild, P. at Zimmerwald Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  1972 UC = 1931 VC1 = 1954 GG = 1971 OR = 1971 QX2  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-19 10:10 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin