+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   161 Athor (A876 HA) Classification: Main-belt Asteroid          SPK-ID: 2000161 [ 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 86 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1375591315161587 3.0822e-08   a 2.379611756812838 5.4636e-09 au q 2.052274430200024 7.4901e-08 au i 9.057055054557756 4.2015e-06 deg node 18.56555543281974 1.9945e-05 deg peri 294.6780859615969 2.5673e-05 deg M 5.096502963885906 1.6604e-05 deg tp 2458981.518638248728 (2020-May-12.01863825) 6.1833e-05 TDB period 1340.780193571761 3.67 4.6176e-06 1.264e-08 d yr n .268500386361601 9.2471e-10 deg/d Q 2.706949083425653 6.2151e-09 au   Orbit Determination Parameters    # obs. used (total)      2628      data-arc span      44227 days (121.09 yr)      first obs. used      1899-10-09      last obs. used      2020-11-10      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .48272      source      ORB      producer      Otto Matic      solution date      2020-Dec-18 01:51:26   Additional Information  Earth MOID = 1.05861 au   Jupiter MOID = 2.60191 au   T_jup = 3.510  [ hide covariance matrix ] Orbital Elements at Epoch 2455104.5 (2009-Sep-30.0) TDB Reference: JPL 86 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1380584858225383 3.0707e-08   q 2.050742439666067 7.4664e-08 au tp 2454958.059545776457 (2009-May-06.55954578) 6.1762e-05 TDB node 18.73710604453317 1.9958e-05 deg peri 294.214031039057 2.5658e-05 deg i 9.055418515776442 4.201e-06 deg   Orbit Determination Parameters    # obs. used (total)      2628      data-arc span      44227 days (121.09 yr)      first obs. used      1899-10-09      last obs. used      2020-11-10      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .48272      source      ORB      producer      Otto Matic      solution date      2020-Dec-18 01:51:26   Additional Information  Jupiter MOID = 2.60191 au   T_jup = 3.510  Orbit Covariance (6×6)   e q tp node peri i e 9.429251213582055E-16 -2.288717607326065E-15 3.184365652251398E-13 -1.518776477654369E-15 5.299865081235947E-14 5.839725669294423E-16 q -2.288717607326065E-15 5.574686546501413E-15 -7.826162099619742E-13 3.473965936927047E-15 -1.307134578113367E-13 -1.376170498614738E-15 tp 3.184365652251398E-13 -7.826162099619742E-13 3.814525589463028E-9 -1.145477312356194E-11 1.001920710058072E-9 -7.093724530066846E-13 node -1.518776477654369E-15 3.473965936927047E-15 -1.145477312356194E-11 3.983076392672757E-10 -3.958454830486484E-10 1.556021924634846E-11 peri 5.299865081235947E-14 -1.307134578113367E-13 1.001920710058072E-9 -3.958454830486484E-10 6.583368826097815E-10 -1.558962309166161E-11 i 5.839725669294423E-16 -1.376170498614738E-15 -7.093724530066846E-13 1.556021924634846E-11 -1.558962309166161E-11 1.764845518734449E-11 [ 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 9.1   n/a MPO492750 IRAS observations used: 25 magnitude slope G 0.13   n/a PDS3 (MPC 17257) Fit diameter diameter 40.992 km 0.694 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   rotation period rot_per 7.280 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Debehogne, H.; Zappala, V. (1980) Astron. Astrophys. Suppl. Ser. 42, 85-89.] [Carlsson, M.; Lagerkvist, C.-I. (1983) Astron. Astrophys. Suppl. Ser. 53, 157-159.] [Harris, A.W.; Young, J.W. (1989) Icarus 81, 314-364.] [Pilcher, F.; Higgins, D. (2008) Minor Planet Bull. 35, 147.] [Pilcher, F. (2011) Minor Planet Bull. 38, 156-158.] [Franco, L.; Pilcher, F.; Higgins, D.; Durech, J. (2012) Minor Planet Bull. 39, 234-236.] geometric albedo albedo 0.230   0.021 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   B-V BV 0.719   0.008 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=10; phase (min.=9.12, mean=12.69, max.=22.47) deg. U-B UB 0.208   0.024 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=10; phase (min.=9.12, mean=12.69, max.=22.47) deg. Tholen spectral type spec_T M   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo SMASSII spectral type spec_B Xc   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) 161 Athor (A876 HA)          Discovered 1876-Apr-19 by Watson, J. C. at Ann Arbor Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  A876 HA = 1961 PF = 1973 YN4 = A899 TA  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Jan-15 21:16 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin