{"orbit":{"not_valid_after":null,"n_dop_obs_used":7,"two_body":null,"not_valid_before":null,"source":"JPL","sb_used":"SB424-N343","producer":"Davide Farnocchia","soln_date":"2021-01-07 11:18:06","t_jup":"5.525","epoch":"2455562.5","first_obs":"1999-09-11","cov_epoch":"2455562.5","comment":"See Farnocchia et al. 2021","orbit_id":"118","elements":[{"title":"eccentricity","label":"e","name":"e","sigma":"7e-11","value":"0.204","units":null},{"units":"au","value":"1.13","sigma":"2e-10","name":"a","title":"semi-major axis","label":"a"},{"units":"au","value":"0.897","sigma":"2.3e-10","name":"q","title":"perihelion distance","label":"q"},{"sigma":"6.9e-09","name":"i","title":"inclination; angle with respect to x-y ecliptic plane","label":"i","units":"deg","value":"6.03"},{"value":"2.06","units":"deg","title":"longitude of the ascending node","label":"node","name":"om","sigma":"5.6e-08"},{"name":"w","sigma":"6.4e-08","title":"argument of perihelion","label":"peri","units":"deg","value":"66.2"},{"title":"mean anomaly","label":"M","sigma":"4.3e-08","name":"ma","units":"deg","value":"102"},{"label":"tp","title":"time of perihelion passage","name":"tp","sigma":"2.3e-08","value":"2455439.142","units":"TDB"},{"title":"sidereal orbital period","label":"period","sigma":"1.1e-07","name":"per","units":"d","value":"437"},{"sigma":"2.2e-10","name":"n","title":"mean motion","label":"n","units":"deg/d","value":"0.824"},{"value":"1.36","units":"au","title":"aphelion distance","label":"Q","name":"ad","sigma":"2.4e-10"}],"last_obs":"2020-10-03","n_del_obs_used":58,"moid_jup":"3.88","model_pars":[{"name":"AMRAT","sigma":"1.908E-7","kind":"EST","title":"area-to-mass ratio","desc":"solar radiation pressure area-to-mass ratio","value":"2.64e-06","units":"m^2/kg","n":2},{"title":"bulk density","desc":"bulk density","sigma":".892","name":"RHO","kind":"EST","n":1,"value":"1190","units":"kg/m^3"}],"n_obs_used":554,"equinox":"J2000","data_arc":"7693","condition_code":"0","rms":"0.29","pe_used":"DE424","moid":"0.00322"},"object":{"pha":true,"orbit_id":"118","orbit_class":{"code":"APO","name":"Apollo"},"prefix":null,"fullname":"101955 Bennu (1999 RQ36)","kind":"an","des":"101955","spkid":"20101955","shortname":"101955 Bennu","neo":true},"phys_par":[{"units":null,"ref":"Hergenrother, M.C., et al., Nat. Commun. 10, 1291 (2019)","value":"20.21","desc":"absolute magnitude (magnitude at 1 au from Sun and observer)","title":"absolute magnitude","name":"H","notes":null,"sigma":"0.03"},{"units":null,"value":"-0.031","ref":"Hergenrother, M.C., et al., Nat. Commun. 10, 1291 (2019)","desc":"magnitude slope parameter used in the standard asteroid H/G magnitude law","title":"magnitude slope","notes":null,"name":"G","sigma":"0.009"},{"units":"km","ref":"Daly, M.G., et al., Sci. Adv. 6, eabd3649 (2020)","value":"0.48444","desc":"effective body diameter","title":"diameter","notes":null,"name":"diameter","sigma":"0.00030"},{"units":"km","ref":"Daly, M.G., et al., Sci. Adv. 6, eabd3649 (2020)","value":"0.5047 x 0.4918 x 0.4567","desc":"tri(or bi)-axial body dimensions","title":"extent","sigma":"0.002 x 0.002 x 0.002","notes":null,"name":"extent"},{"desc":"standard gravitational parameter: product of the mass (M) and gravitational constant (G)","title":"GM","sigma":"0.0009e-9","notes":null,"name":"GM","units":"km^3/s^2","value":"4.8904e-9","ref":"Chesley, S.R., et al., J. Geophys. Res. (Planets) 125, e06363 (2020)"},{"units":"g/cm^3","value":"1.194","ref":"Daly, M.G., et al., Sci. Adv. 6, eabd3649 (2020)","title":"bulk density","desc":"bulk density","notes":null,"sigma":"0.003","name":"density"},{"notes":"J2000 epoch","sigma":"0.000002","name":"rot_per","title":"rotation period","desc":"body rotation period (synodic)","units":"h","ref":"Hergenrother, M.C., et al., Nat. Commun. 10, 1291 (2019)","value":"4.296061"},{"units":"rad/d^2","value":"6.34e-8","ref":"Hergenrother, M.C., et al., Nat. Commun. 10, 1291 (2019)","desc":"Rate of change of angular velocity","title":"rotational acceleration","name":"rot_acc","notes":null,"sigma":"0.91e-8"},{"notes":null,"name":"pole","sigma":"0.0003/0.0001","title":"pole direction","desc":"spin-pole direction in R.A./Dec.","ref":"Daly, M.G., et al., Sci. Adv. 6, eabd3649 (2020)","value":"85.4522/-60.3678","units":null},{"ref":"Hergenrother, M.C., et al., Nat. Commun. 10, 1291 (2019)","value":"0.044","units":null,"notes":null,"name":"albedo","sigma":"0.002","desc":"geometric albedo","title":"geometric albedo"},{"value":"300","ref":"Rozitis, B., et al., Sci. Adv. 6, eabc3699 (2020)","units":"J/m^2/s^0.5/K","notes":null,"sigma":"30","name":"I","desc":"Thermal inertia of the small-body surface","title":"thermal inertia"},{"value":"0.64","ref":"Hergenrother, C.W. et al. Icarus 226, 663-670 (2013)","units":null,"title":"B-V","desc":"color index B-V magnitude difference","notes":null,"name":"BV","sigma":"0.04"},{"units":null,"ref":"Hergenrother, C.W. et al. Icarus 226, 663-670 (2013)","value":"0.16","sigma":"0.05","notes":null,"name":"UB","title":"U-B","desc":"color index U-B magnitude difference"},{"ref":"Hergenrother, C.W. et al. Icarus 226, 663-670 (2013)","value":"-0.33","units":null,"desc":"color index I-R magnitude difference","title":"I-R","name":"IR","notes":null,"sigma":"0.06"},{"units":null,"value":"B","ref":"Clark, B.E., et al., Icarus 216, 462-475 (2011)","sigma":null,"notes":null,"name":"spec_B","title":"SMASSII spectral type","desc":"SMASSII spectral taxonomic classification"}],"signature":{"source":"NASA/JPL Small-Body Database (SBDB) API","version":"1.3"}}