{"signature":{"source":"NASA/JPL Small-Body Database (SBDB) API","version":"1.3"},"orbit":{"not_valid_after":null,"rms":"0.33","first_obs":"1856-10-29","pe_used":"DE441","epoch":"2461200.5","sb_used":"SB441-N16","two_body":null,"moid":"1.08","source":"JPL","equinox":"J2000","n_obs_used":10321,"last_obs":"2026-04-07","t_jup":"3.507","data_arc":"61886","model_pars":[],"cov_epoch":"2458004.5","n_dop_obs_used":null,"not_valid_before":null,"soln_date":"2026-06-05 03:03:25","producer":"Otto Matic","orbit_id":"144","comment":null,"moid_jup":"2.39","n_del_obs_used":null,"condition_code":"0","elements":[{"title":"eccentricity","name":"e","value":"0.144","label":"e","units":null,"sigma":"3e-09"},{"title":"semi-major axis","name":"a","value":"2.41","label":"a","units":"au","sigma":"1.3e-09"},{"label":"q","units":"au","sigma":"7.1e-09","name":"q","title":"perihelion distance","value":"2.06"},{"value":"0.709","name":"i","title":"inclination; angle with respect to x-y ecliptic plane","sigma":"2.5e-07","units":"deg","label":"i"},{"title":"longitude of the ascending node","name":"om","value":"206","label":"node","units":"deg","sigma":"2.3e-05"},{"label":"peri","units":"deg","sigma":"2.3e-05","name":"w","title":"argument of perihelion","value":"257"},{"sigma":"1.2e-06","units":"deg","label":"M","value":"82.8","title":"mean anomaly","name":"ma"},{"label":"tp","units":"TDB","sigma":"4.3e-06","title":"time of perihelion passage","name":"tp","value":"2460886.589"},{"label":"period","sigma":"1.1e-06","units":"d","value":"1360","name":"per","title":"sidereal orbital period"},{"label":"n","sigma":"2.1e-10","units":"deg/d","value":"0.264","title":"mean motion","name":"n"},{"label":"Q","sigma":"1.5e-09","units":"au","value":"2.75","name":"ad","title":"aphelion distance"}]},"phys_par":[{"notes":"IRAS observations used: 9","desc":"absolute magnitude (magnitude at 1 au from Sun and observer)","ref":"MPO745323","value":"6.54","name":"H","sigma":null,"units":null,"title":"absolute magnitude"},{"title":"magnitude slope","units":null,"sigma":null,"desc":"magnitude slope parameter used in the standard asteroid H/G magnitude law","name":"G","value":"0.25","ref":"PDS3 (MPC 17257)","notes":"Fit"},{"sigma":"3.674","units":"km","title":"diameter","notes":null,"desc":"effective body diameter","ref":"urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)","value":"135.680","name":"diameter"},{"units":"h","sigma":null,"title":"rotation period","notes":"REFERENCE LIST:[Gehrels, T. (1956) Astrophys. J. 123, 331-338.], [Chang, Y.C.; Chang, C.-s. (1962) Acta Astron. Sin. 10, 101-111.], [Magnusson, P. (1986) Icarus 68, 1-39.], [Dotto, E.; De Angelis, G.; Di Martino, M.; Barucci, M.A.; et al. (1995) Icarus 117, 313-327.], [Hainaut-Rouelle, M.-C.; Hainaut, O.R.; Detal, A. (1995) Astron. Astrophys. Suppl. Ser. 112, 125-142.], [Szabo, Gy.; Sarneczky, K.; Kiss, L.L. (1999) in Proc. IAU Coll. 173, Evolution and Source Regions of Asteroids and Comets, 185-188.], [Kaasalainen, M.; Torppa, J.; Piironen, J. (2002) Icarus 159, 369-395.], [Bel'skaya, I.N.; Shevchenko, V.G.; Kiselev, N.; Krugly, Yu.N.; et al. (2003) Icarus 166, 276-284.], [Higgins, D.J. (2012) http://www.david-higgins.com/Astronomy/asteroid/lightcurves.htm], [Hanus, J.; Durech, J.; Oszkiewicz, D.A.; Behrend, R.; et al. (2016) Astron. Astrophys. 586, A108.], [Behrend, R. (2018) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html], [Cellino, A.; Hestroffer, D.; Lu, X.-P.; Muinonen, K.; Tanga, P. (2019) Astron. Astrophys. 631, A67.], [Podlewska-Gaca, E.; Marciniak, A.; Ali-Lagoa, V.; Bartczak, P.; et al. (2020) Astron. Astrophys. 638, id A11.], [Ferrais, M.; Vernazza, P.; Jorda, L.; Jehin, E.; et al. (2022) Minor Planet Bull. 49, 307-313.]","name":"rot_per","value":"8.098","ref":"LCDB (Rev. 2023-October); Warner et al., 2009","desc":"body rotation period (synodic)"},{"notes":null,"name":"albedo","ref":"urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)","value":"0.241","desc":"geometric albedo","units":null,"sigma":"0.018","title":"geometric albedo"},{"sigma":"0.019","units":null,"title":"B-V","notes":"#obs=38; phase (min.=1.22, mean=9.15, max.=27.29) deg.","value":"0.854","ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","name":"BV","desc":"color index B-V magnitude difference"},{"name":"UB","value":"0.463","ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","desc":"color index U-B magnitude difference","notes":"#obs=37; phase (min.=1.65, mean=9.37, max.=27.29) deg.","title":"U-B","units":null,"sigma":"0.034"},{"title":"Tholen spectral type","units":null,"sigma":null,"name":"spec_T","value":"S","ref":"EAR-A-5-DDR-TAXONOMY-V4.0","desc":"Tholen spectral taxonomic classification","notes":"used 7 color indices; used ground-based radiometric albedo"},{"units":null,"sigma":null,"title":"SMASSII spectral type","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"}],"object":{"spkid":"20000020","neo":false,"shortname":"20 Massalia","des":"20","kind":"an","orbit_id":"144","pha":false,"prefix":null,"orbit_class":{"code":"MBA","name":"Main-belt Asteroid"},"fullname":"20 Massalia (A852 SA)"}}