{"object":{"fullname":"29 Amphitrite (A854 EB)","orbit_class":{"code":"MBA","name":"Main-belt Asteroid"},"pha":false,"prefix":null,"orbit_id":"175","kind":"an","des":"29","shortname":"29 Amphitrite","neo":false,"spkid":"20000029"},"signature":{"source":"NASA/JPL Small-Body Database (SBDB) API","version":"1.3"},"orbit":{"data_arc":"62340","model_pars":[],"cov_epoch":"2458019.5","last_obs":"2026-03-30","t_jup":"3.427","not_valid_before":null,"n_dop_obs_used":null,"source":"JPL","equinox":"J2000","moid":"1.39","two_body":null,"n_obs_used":3549,"first_obs":"1855-07-25","pe_used":"DE441","epoch":"2461200.5","sb_used":"SB441-N16","not_valid_after":null,"rms":"0.51","n_del_obs_used":null,"comment":null,"moid_jup":"2.49","condition_code":"0","elements":[{"label":"e","units":null,"sigma":"2.5e-09","name":"e","title":"eccentricity","value":"0.0732"},{"value":"2.55","name":"a","title":"semi-major axis","sigma":"1.6e-09","units":"au","label":"a"},{"value":"2.37","title":"perihelion distance","name":"q","label":"q","sigma":"6.8e-09","units":"au"},{"sigma":"3.3e-07","units":"deg","label":"i","value":"6.08","name":"i","title":"inclination; angle with respect to x-y ecliptic plane"},{"sigma":"3e-06","units":"deg","label":"node","value":"356","name":"om","title":"longitude of the ascending node"},{"title":"argument of perihelion","name":"w","value":"61.9","units":"deg","sigma":"4e-06","label":"peri"},{"name":"ma","title":"mean anomaly","value":"193","units":"deg","sigma":"2.9e-06","label":"M"},{"name":"tp","title":"time of perihelion passage","value":"2461890.764","label":"tp","units":"TDB","sigma":"1.2e-05"},{"name":"per","title":"sidereal orbital period","value":"1490","units":"d","sigma":"1.4e-06","label":"period"},{"label":"n","sigma":"2.3e-10","units":"deg/d","value":"0.241","name":"n","title":"mean motion"},{"value":"2.74","title":"aphelion distance","name":"ad","sigma":"1.8e-09","units":"au","label":"Q"}],"producer":"Otto Matic","orbit_id":"175","soln_date":"2026-06-05 03:03:25"},"phys_par":[{"notes":"IRAS observations used: 11","desc":"absolute magnitude (magnitude at 1 au from Sun and observer)","name":"H","ref":"MPO980521","value":"5.97","units":null,"sigma":null,"title":"absolute magnitude"},{"title":"magnitude slope","units":null,"sigma":null,"name":"G","value":"0.20","ref":"PDS3 (MPC 17257)","desc":"magnitude slope parameter used in the standard asteroid H/G magnitude law","notes":"Fit"},{"units":"km","sigma":"1.129","title":"diameter","notes":null,"desc":"effective body diameter","name":"diameter","ref":"urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)","value":"189.559"},{"notes":"REFERENCE LIST:[Chang, Y.C.; Chang, C.-S. (1963) Acta Astron. Sin. 11, 139-149.], [Debehogne, H.; Surdej, A.; Surdej, J. (1978) Astron. Astrophys. Suppl. Ser. 32, 127-133.], [Van Houten-Groeneveld, I.; van Houten, C.J.; Zappala, V. (1979) Astron. Astrophys. Suppl. Ser. 35, 223-232.], [Tedesco, E.F.; Sather, R.E. (1981) Astron. J. 86, 1553-1558.], [Magnusson, P. (1986) Icarus 68, 1-39.], [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.], [De Angelis, G. (1995) Planet. Space Sci. 43, 649-682.], [Kaasalainen, M.; Torppa, J.; Piironen, J. (2002) Icarus 159, 369-395.], [Behrend, R. (2006) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Behrend, R. (2007) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Behrend, R. (2009) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [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.], [Hanus, J.; Durech, J.; Oszkiewicz, D.A.; Behrend, R.; et al. (2016) Astron. Astrophys. 586, A108.], [Behrend, R. (2017) 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.], [Cellino, A.; Hestroffer, D.; Lu, X.-P.; Muinonen, K.; Tanga, P. (2019) Astron. Astrophys. 631, A67.], [Vernazza, P.; Ferrais, M.; Jorda, L.; Hanus, J.; et al. (2021) Astron. Astrophys 654, id. A56.]","desc":"body rotation period (synodic)","name":"rot_per","value":"5.3921","ref":"LCDB (Rev. 2023-October); Warner et al., 2009","units":"h","sigma":null,"title":"rotation period"},{"title":"geometric albedo","units":null,"sigma":"0.043","name":"albedo","value":"0.216","ref":"urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)","desc":"geometric albedo","notes":null},{"units":null,"sigma":"0.020","title":"B-V","notes":"#obs=60; phase (min.=.46, mean=10.77, max.=24.12) deg.","name":"BV","ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","value":"0.838","desc":"color index B-V magnitude difference"},{"units":null,"sigma":"0.049","title":"U-B","notes":"#obs=46; phase (min.=.46, mean=8.83, max.=23.91) deg.","name":"UB","value":"0.449","ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","desc":"color index U-B magnitude difference"},{"title":"Tholen spectral type","sigma":null,"units":null,"value":"S","ref":"EAR-A-5-DDR-TAXONOMY-V4.0","name":"spec_T","desc":"Tholen spectral taxonomic classification","notes":"used 7 color indices; used ground-based radiometric albedo"},{"notes":"based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)","name":"spec_B","value":"S","ref":"EAR-A-5-DDR-TAXONOMY-V4.0","desc":"SMASSII spectral taxonomic classification","units":null,"sigma":null,"title":"SMASSII spectral type"}]}