+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   1025 Riema (A923 PG) Classification: Inner Main-belt Asteroid          SPK-ID: 2001025 [ 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 38 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .03915685680896892 3.4484e-08   a 1.979193513803171 3.8384e-09 au q 1.90169451678594 6.7178e-08 au i 26.86207042254947 3.6536e-06 deg node 163.3749147578716 7.392e-06 deg peri 349.1472311139017 4.6901e-05 deg M 96.24929698645528 4.7389e-05 deg tp 2458728.589561215793 (2019-Sep-02.08956122) 0.00013372 TDB period 1017.023095515074 2.78 2.9586e-06 8.1e-09 d yr n .3539742623226043 1.0297e-09 deg/d Q 2.056692510820401 3.9887e-09 au   Orbit Determination Parameters    # obs. used (total)      2731      data-arc span      35421 days (96.98 yr)      first obs. used      1923-08-13      last obs. used      2020-08-04      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .37861      source      ORB      producer      Otto Matic      solution date      2020-Aug-24 22:26:38   Additional Information  Earth MOID = .911197 au   Jupiter MOID = 2.92157 au   T_jup = 3.729  [ 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 12.5   n/a MPO467621   diameter diameter 4.605 km 0.171 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   rotation period rot_per 3.588 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List: [Stephens, R.D. (2003) Minor Planet Bull. 30, 69-70.] [Warner, B.D. (2009) Minor Planet Bull. 36, 172-176.] [Warner, B.D. (2013). Minor Planet Bull. 40, 26-29.] [Warner, B.D. (2014) Minor Planet Bull. 41, 144-155.] [Warner, B.D. (2016) Minor Planet Bull. 43, 57-65.] [Behrend, R. (2017) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Warner, B.D. (2017) Minor Planet Bull. 44, 213-219.] [Tan, H.; Yeh, T.; Li, B.; Gao, X. (2018) Minor Planet Bull. 45, 57-59.] geometric albedo albedo 1.000   0.000 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   B-V BV 0.714   0.022 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=28.96 deg. U-B UB 0.294   0.037 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=28.96 deg. Tholen spectral type spec_T E   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo SMASSII spectral type spec_B Xe   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002) 1025 Riema (A923 PG)          Discovered 1923-Aug-12 by Reinmuth, K. at Heidelberg Reference: DISCOVERY.DB Last Updated: 2003-08-29 Alternate Designations  A923 PG = A923 QA  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2020-Sep-29 16:11 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin