{"signature":{"version":"1.3","source":"NASA/JPL Small-Body Database (SBDB) API"},"object":{"fullname":"87 Sylvia (A866 KA)","pha":false,"prefix":null,"orbit_class":{"name":"Outer Main-belt Asteroid","code":"OMB"},"spkid":"20000087","kind":"an","neo":false,"des":"87","shortname":"87 Sylvia","orbit_id":"130"},"orbit":{"comment":null,"cov_epoch":"2458183.5","producer":"Otto Matic","n_dop_obs_used":null,"two_body":null,"orbit_id":"130","pe_used":"DE441","elements":[{"name":"e","label":"e","units":null,"sigma":"2.2e-09","title":"eccentricity","value":"0.0942"},{"label":"a","name":"a","value":"3.49","sigma":"5.6e-09","units":"au","title":"semi-major axis"},{"name":"q","label":"q","sigma":"4.9e-09","units":"au","title":"perihelion distance","value":"3.16"},{"value":"10.8","units":"deg","sigma":"1.7e-07","title":"inclination; angle with respect to x-y ecliptic plane","name":"i","label":"i"},{"name":"om","label":"node","value":"72.9","sigma":"6.1e-07","units":"deg","title":"longitude of the ascending node"},{"label":"peri","name":"w","title":"argument of perihelion","sigma":"1.4e-06","units":"deg","value":"267"},{"name":"ma","label":"M","value":"124","units":"deg","sigma":"1.8e-06","title":"mean anomaly"},{"value":"2460380.434","sigma":"1e-05","units":"TDB","title":"time of perihelion passage","label":"tp","name":"tp"},{"label":"period","name":"per","value":"2380","units":"d","sigma":"5.8e-06","title":"sidereal orbital period"},{"value":"0.151","title":"mean motion","units":"deg/d","sigma":"3.7e-10","label":"n","name":"n"},{"units":"au","sigma":"6.2e-09","title":"aphelion distance","value":"3.82","label":"Q","name":"ad"}],"soln_date":"2026-06-05 03:08:26","data_arc":"51469","not_valid_before":null,"model_pars":[],"epoch":"2461200.5","moid":"2.18","first_obs":"1885-05-05","n_obs_used":7387,"not_valid_after":null,"equinox":"J2000","rms":"0.33","moid_jup":"1.57","last_obs":"2026-04-05","n_del_obs_used":null,"condition_code":"0","sb_used":"SB441-N16","t_jup":"3.092","source":"JPL"},"phys_par":[{"notes":"IRAS observations used: 20","value":"6.93","title":"absolute magnitude","ref":"MPO950948","sigma":null,"units":null,"name":"H","desc":"absolute magnitude (magnitude at 1 au from Sun and observer)"},{"value":"253.051","notes":null,"sigma":"2.953","units":"km","title":"diameter","ref":"urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)","desc":"effective body diameter","name":"diameter"},{"name":"rot_per","desc":"body rotation period (synodic)","ref":"LCDB (Rev. 2023-October); Warner et al., 2009","title":"rotation period","units":"h","sigma":null,"notes":"REFERENCE LIST:[Schober, H.J.; Surdej, J. (1979) Astron. Astrophys. Suppl. Ser. 38, 269-274.], [Harris, A.W.; Young, J.W. (1980) Icarus 43, 20-32.], [Weidenschilling, S.J.; Chapman, C.R.; Davis, D.R.; Greenberg, R.; et al. (1987) Icarus 70, 191-245.], [Drummond, J.D.; Weidenschilling, S.J.; Chapman, C.R.; Davis, D.R. (1988) Icarus 76, 19-77.], [Magnusson, P. (1990) Icarus 85, 229-240.], [Drummond, J.D.; Weidenschilling, S.J.; Chapman, C.R.; Davis, D.R. (1991) Icarus 89, 44-64.], [Michalowski, T. (1993) Icarus 106, 563-572.], [De Angelis, G. (1995) Planet. Space Sci. 43, 649-682.], [Foerster, I.; Potthoff, H. (2001) Minor Planet Bull. 28, 25-26.], [Kaasalainen, M.; Torppa, J.; Piironen, J. (2002) Icarus 159, 369-395.], [Marchis, F.; Kaasalainen, M.; Hom, E.F.Y.; Berthier, J.; et al. (2006) Icarus 185, 39-63.], [Behrend, R. (2007) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Vereshchagina, I.A.; Gorshanov, D.L.; Devyatkin, A.V.; Papushev, P.G. (2009) Solar System Research 43, 291-300.], [Hamanowa, H.; Hamanowa, H. (2011) http://www2.ocn.ne.jp/~hamaten/astlcdata.htm], [Behrend, R. (2012) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Hanus, J.; Marchis, F.; Durech, J. (2013) Icarus 226, 1045-1057.], [Behrend, R. (2015) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Hanus, J.; Durech, J.; Oszkiewicz, D.A.; Behrend, R.; et al. (2016) Astron. Astrophys. 586, A108.], [Hanus, J.; Viikinkoski, M.; Marchis, F.; Durech, J.; et al (2017) Astron. Astrophys. 601, A114.], [Carry, B.; Vernazza, P.; Vachier, F.; Neveu, M.; et al. (2021) Astron. Astrophys 650, A129.], [Behrend, R. (2021) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Vernazza, P.; Ferrais, M.; Jorda, L.; Hanus, J.; et al. (2021) Astron. Astrophys 654, id. A56.], [Benishek, V. (2022) Minor Planet Bull. 49, 333-341.], [Ferrais, M.; Vernazza, P.; Jorda, L.; Jehin, E.; et al. (2022) Minor Planet Bull. 49, 307-313.]","value":"5.184"},{"name":"albedo","desc":"geometric albedo","title":"geometric albedo","ref":"urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)","sigma":"0.004","units":null,"notes":null,"value":"0.046"},{"desc":"color index B-V magnitude difference","name":"BV","sigma":"0.015","units":null,"ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","title":"B-V","value":"0.710","notes":"#obs=19; phase (min.=3.98, mean=10.21, max.=17.32) deg."},{"title":"U-B","ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","sigma":"0.026","units":null,"notes":"#obs=9; phase (min.=5.07, mean=8.15, max.=15.60) deg.","value":"0.251","name":"UB","desc":"color index U-B magnitude difference"},{"desc":"Tholen spectral taxonomic classification","name":"spec_T","sigma":null,"units":null,"title":"Tholen spectral type","ref":"EAR-A-5-DDR-TAXONOMY-V4.0","value":"P","notes":"used 7 color indices; used ground-based radiometric albedo"},{"name":"spec_B","desc":"SMASSII spectral taxonomic classification","title":"SMASSII spectral type","ref":"EAR-A-5-DDR-TAXONOMY-V4.0","sigma":null,"units":null,"notes":"based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)","value":"X"}]}