+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   85 Io (A865 SA) Classification: Main-belt Asteroid          SPK-ID: 2000085 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 106 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1946308729643396 2.97e-08   a 2.653205634376388 4.3995e-09 au q 2.136809905603807 7.9463e-08 au i 11.95913368828365 3.141e-06 deg node 203.0704107879164 1.6108e-05 deg peri 122.8329757426631 1.7837e-05 deg M 357.8022610090651 8.839e-06 deg tp 2459210.136701475786 (2020-Dec-26.63670148) 3.8767e-05 TDB period 1578.537099078853 4.32 3.9262e-06 1.075e-08 d yr n .2280592582905249 5.6725e-10 deg/d Q 3.169601363148968 5.2558e-09 au   Orbit Determination Parameters    # obs. used (total)      2969      data-arc span      56703 days (155.24 yr)      first obs. used      1865-09-21      last obs. used      2020-12-20      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .46274      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 00:43:17   Additional Information  Earth MOID = 1.15147 au   Jupiter MOID = 2.33496 au   T_jup = 3.332  [ 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 7.75   n/a E2021B10 IRAS observations used: 8 diameter diameter 154.79 km 3.8 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 8 rotation period rot_per 6.875 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Yang, X.-y.; Zhang, Y.-y.; Li, X.-q. (1965) Acta Astron. Sin. 13, 66-74.] [Lagerkvist, C.-I.; Schober, H.J. (1981) Astron. Astrophys. Suppl. Ser. 44, 401-404.] [Erikson, A.; Berthier, J.; Denchev, P.V.; Harris, A.W.; et al. (1999) Planet. Space Sci. 47, 327-330.] [Torppa, J.; Kaasalainen, M.; Michalowski, T.; Kwiatkowski, T.; et al. (2003) Icarus 164, 346-383.] [Behrend, R. (2005) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Behrend, R. (2006) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Behrend, R. (2011) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Durech, J.; Kaasalainen, M.; Herald, D.; Dunham, D.; et al. (2011) Icarus 214, 652-670.] [Hanus, J.; Marchis, F.; Durech, J. (2013) Icarus 226, 1045-1057.] [Behrend, R. (2016) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Hanus, J.; Viikinkoski, M.; Marchis, F.; Durech, J.; et al (2017) Astron. Astrophys. 601, A114.] [Carbognani, A.; Cellino, A.; Caminiti, S. (2019) Planet. Space Sci. 169, 15-34.] [Pal, A.; Szakats, R.; Kiss, C.; Bodi, A.; et al. (2019) Ap. J. Supl. Ser. 247, id.26.] geometric albedo albedo 0.0666   0.003 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 8 B-V BV 0.668   0.023 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=8; phase (min.=6.05, mean=11.20, max.=19.29) deg. U-B UB 0.294   0.015 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=7; phase (min.=6.05, mean=10.95, max.=19.29) deg. Tholen spectral type spec_T FC   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo SMASSII spectral type spec_B B   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) 85 Io (A865 SA)          Discovered 1865-Sep-19 by Peters, C. H. F. at Clinton Reference: DISCOVERY.DB Last Updated: 2003-08-29 Alternate Designations  A865 SA = A899 LA = A899 UA  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Mar-03 00:55 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin