{"object":{"prefix":null,"shortname":"4 Vesta","fullname":"4 Vesta (A807 FA)","neo":false,"spkid":"20000004","orbit_class":{"name":"Main-belt Asteroid","code":"MBA"},"des":"4","kind":"an","pha":false,"orbit_id":"36"},"orbit":{"n_del_obs_used":2977,"not_valid_before":null,"n_obs_used":9451,"comment":null,"last_obs":"2021-03-17","condition_code":"0","sb_used":"SB441-N16","rms":"0.4","not_valid_after":null,"n_dop_obs_used":0,"moid_jup":"2.46","two_body":null,"producer":"Davide Farnocchia","soln_date":"2021-04-13 11:15:57","equinox":"J2000","orbit_id":"36","epoch":"2461200.5","t_jup":"3.535","data_arc":"25743","cov_epoch":"2458849.5","elements":[{"units":null,"label":"e","sigma":"2.3e-10","name":"e","title":"eccentricity","value":"0.0902"},{"label":"a","units":"au","value":"2.36","title":"semi-major axis","sigma":"1.5e-09","name":"a"},{"label":"q","units":"au","value":"2.15","title":"perihelion distance","sigma":"1.9e-09","name":"q"},{"sigma":"2.2e-07","title":"inclination; angle with respect to x-y ecliptic plane","name":"i","value":"7.14","units":"deg","label":"i"},{"label":"node","units":"deg","value":"104","name":"om","sigma":"3.9e-07","title":"longitude of the ascending node"},{"label":"peri","units":"deg","value":"151","sigma":"1.9e-07","name":"w","title":"argument of perihelion"},{"title":"mean anomaly","sigma":"1.9e-06","name":"ma","value":"81.2","units":"deg","label":"M"},{"label":"tp","units":"TDB","value":"2460901.587","sigma":"6.7e-06","name":"tp","title":"time of perihelion passage"},{"units":"d","label":"period","name":"per","sigma":"1.3e-06","title":"sidereal orbital period","value":"1330"},{"title":"mean motion","sigma":"2.6e-10","name":"n","value":"0.272","units":"deg/d","label":"n"},{"units":"au","label":"Q","name":"ad","sigma":"1.7e-09","title":"aphelion distance","value":"2.57"}],"model_pars":[],"first_obs":"1950-09-23","pe_used":"DE441","moid":"1.14","source":"JPL"},"signature":{"version":"1.3","source":"NASA/JPL Small-Body Database (SBDB) API"},"discovery":{"site":null,"citation":null,"discovery":"Discovered 1807-03-29 by Olbers, H. W. at Bremen","ref":"DISCOVERY.DB","name":null,"cref":null,"date":"1807-Mar-29","location":"Bremen","who":"Olbers, H. W."},"phys_par":[{"units":null,"ref":"E2024D82","notes":"IRAS observations used: 2","desc":"absolute magnitude (magnitude at 1 au from Sun and observer)","sigma":null,"name":"H","title":"absolute magnitude","value":"3.25"},{"units":null,"ref":"PDS3 (MPC 17257)","notes":"Fit","sigma":null,"name":"G","title":"magnitude slope","value":"0.32","desc":"magnitude slope parameter used in the standard asteroid H/G magnitude law"},{"units":"km","ref":"Park, R.S. et al. 2025, Nat Astron, DOI: 10.1038/s41550-025-02533-7","notes":null,"title":"diameter","sigma":"0.1","name":"diameter","value":"522.77","desc":"effective body diameter"},{"desc":"tri(or bi)-axial body dimensions","value":"569.24 x 554.48 x 452.66","sigma":"0.1 x 0.1 x 0.1","name":"extent","title":"extent","notes":null,"ref":"Park, R.S. et al. 2025, Nat Astron, DOI: 10.1038/s41550-025-02533-7","units":"km"},{"value":"17.2882844","name":"GM","sigma":"0.0000030","title":"GM","desc":"standard gravitational parameter: product of the mass (M) and gravitational constant (G)","notes":null,"ref":"Park, R.S. et al. 2025, Nat Astron, DOI: 10.1038/s41550-025-02533-7","units":"km^3/s^2"},{"value":"3.460","sigma":"0.005","title":"bulk density","name":"density","desc":"bulk density","notes":null,"units":"g/cm^3","ref":"Park, R.S. et al. 2025, Nat Astron, DOI: 10.1038/s41550-025-02533-7"},{"sigma":"0.0000000004","title":"rotation period","name":"rot_per","value":"5.3421276322","desc":"body rotation period (synodic)","ref":"Park, R.S. et al. 2025, Nat Astron, DOI: 10.1038/s41550-025-02533-7","units":"h","notes":"Rotation rate (deg/day): 1617.33312922 +/- 0.00000013"},{"units":null,"ref":"Park, R.S. et al. 2025, Nat Astron, DOI: 10.1038/s41550-025-02533-7","notes":"values in degrees","desc":"spin-pole direction in R.A./Dec.","sigma":"0.00031/0.000068","title":"pole direction","name":"pole","value":"309.06110/42.232386"},{"notes":"IRAS observations used: 2","ref":"IRAS-A-FPA-3-RDR-IMPS-V6.0","units":null,"value":"0.4228","sigma":"0.053","title":"geometric albedo","name":"albedo","desc":"geometric albedo"},{"notes":"#obs=23; phase (min.=1.73, mean=14.92, max.=24.69) deg.","units":null,"ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","desc":"color index B-V magnitude difference","value":"0.782","title":"B-V","sigma":"0.020","name":"BV"},{"units":null,"ref":"EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2","notes":"#obs=23; phase (min.=1.73, mean=15.34, max.=24.69) deg.","sigma":"0.030","name":"UB","title":"U-B","value":"0.492","desc":"color index U-B magnitude difference"},{"ref":"EAR-A-5-DDR-TAXONOMY-V4.0","units":null,"notes":"used 7 color indices; used ground-based radiometric albedo","desc":"Tholen spectral taxonomic classification","title":"Tholen spectral type","sigma":null,"name":"spec_T","value":"V"},{"sigma":null,"title":"SMASSII spectral type","name":"spec_B","value":"V","desc":"SMASSII spectral taxonomic classification","ref":"EAR-A-5-DDR-TAXONOMY-V4.0","units":null,"notes":"based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)"}]}