+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   91 Aegina (A866 VA) Classification: Main-belt Asteroid          SPK-ID: 2000091 [ 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 125 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1064970764240596 3.1975e-08   a 2.589074787619766 4.9914e-09 au q 2.313345892095017 8.4056e-08 au i 2.103400640393034 3.096e-06 deg node 10.44066446707581 9.4581e-05 deg peri 74.38266036100086 9.5998e-05 deg M 308.5488955416686 1.6333e-05 deg tp 2459417.974089528047 (2021-Jul-22.47408953) 6.9265e-05 TDB period 1521.651926704547 4.17 4.4003e-06 1.205e-08 d yr n .2365849861470321 6.8415e-10 deg/d Q 2.864803683144514 5.5229e-09 au   Orbit Determination Parameters    # obs. used (total)      3197      data-arc span      56363 days (154.31 yr)      first obs. used      1866-11-10      last obs. used      2021-03-05      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .46717      source      ORB      producer      Otto Matic      solution date      2021-Apr-12 10:16:37   Additional Information  Earth MOID = 1.33021 au   Jupiter MOID = 2.3126 au   T_jup = 3.412  [ 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 8.89   n/a E2021B10 IRAS observations used: 6 diameter diameter 103.402 km 0.483 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 6.025 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Harris, A.W.; Young, J.W. (1980) Icarus 43, 20-32.] [Shevchenko, V.G.; Piironen, J.; Erikson, A.; Bel'skaya, I.N.; et al. (1997) Planet. Space Sci. 45, 1615-1623.] [Warner, B.D. (2009) Minor Planet Bull. 36, 109-116.] [Franco, L.; Marchini, A.; Baj, G.; Scarfi, G.; et al. (2018) Minor Planet Bull. 45, 399-400.] geometric albedo albedo 0.048   0.005 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   B-V BV 0.724   0.014 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=3; phase (min.=4.15, mean=9.96, max.=21.15) deg. U-B UB 0.317   0.035 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=3; phase (min.=4.15, mean=9.96, max.=21.15) deg. Tholen spectral type spec_T CP   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 2 color indices; used ground-based radiometric albedo SMASSII spectral type spec_B Ch   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) 91 Aegina (A866 VA)          Discovered 1866-Nov-04 by Stephan, E. at Marseille Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-13 19:41 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin