{"discovery":{"ref":"20050622/Numbers.arc","name":"Apophis","who":"Tholen, D. J.","discovery":"Discovered 2004 June 19 by R. A. Tucker, D. J. Tholen and F. Bernardi at Kitt Peak.","site":null,"citation":"Also known as Apep, the Destroyer, Apophis is the Egyptian god of evil and destruction who dwelled in eternal darkness.  As a result of its passage within 40 000 km of the earth on 2029 Apr. 13, this minor planet will move from the Aten to the Apollo class.","date":"2004-Jun-19","cref":"20050721/MPCPages.arc","location":"Kitt Peak"},"phys_par":[{"title":"absolute magnitude","sigma":"0.19","notes":null,"value":"19.09","units":null,"name":"H","ref":"Pravec et al., Icarus 233, 48-60 (2014)","desc":"absolute magnitude (magnitude at 1 au from Sun and observer)"},{"notes":"Assumed based on Warner et al., Icarus 202, 1340146 (2009)","sigma":"0.11","title":"magnitude slope","desc":"magnitude slope parameter used in the standard asteroid H/G magnitude law","ref":"Pravec et al., Icarus 233, 48-60 (2014)","name":"G","units":null,"value":"0.24"},{"units":"km","value":"0.34","ref":"Brozovic et al., Icarus 300, 115-128 (2018)","name":"diameter","desc":"effective body diameter","title":"diameter","sigma":"0.04","notes":"Based on 3D shape model derived from radar observations in 2012-2013"},{"desc":"body rotation period (synodic)","ref":"Pravec et al., Icarus 233, 48-60 (2014)","name":"rot_per","value":"30.56","units":"h","notes":null,"sigma":"0.01","title":"rotation period"},{"desc":"geometric albedo","name":"albedo","ref":"Brozovic et al., Icarus 300, 115-128 (2018)","value":"0.35","units":null,"notes":null,"sigma":"0.10","title":"geometric albedo"},{"sigma":null,"notes":null,"title":"thermal inertia","desc":"Thermal inertia of the small-body surface","value":"50-500","units":"J/m^2/s^0.5/K","ref":"Licandro et al., A&A 585, A10 (2016)","name":"I"},{"name":"spec_B","ref":"Binzel, R. P. et al.  Icarus 200 (2009) 480-485","units":null,"value":"Sq","desc":"SMASSII spectral taxonomic classification","title":"SMASSII spectral type","notes":null,"sigma":null}],"object":{"kind":"an","neo":true,"des":"99942","fullname":"99942 Apophis (2004 MN4)","pha":true,"prefix":null,"spkid":"20099942","orbit_id":"220","orbit_class":{"code":"ATE","name":"Aten"},"shortname":"99942 Apophis"},"signature":{"source":"NASA/JPL Small-Body Database (SBDB) API","version":"1.3"},"orbit":{"first_obs":"2004-03-15","n_del_obs_used":20,"equinox":"J2000","sb_used":"SB441-N16","moid_jup":"4.12","condition_code":"0","moid":"0.000108","epoch":"2461200.5","data_arc":"6599","two_body":null,"not_valid_after":null,"not_valid_before":null,"soln_date":"2024-06-25 10:48:08","last_obs":"2022-04-09","orbit_id":"220","n_dop_obs_used":30,"rms":"0.26","cov_epoch":"2459215.5","model_pars":[{"title":"non-grav. radial accel.","kind":"EST","sigma":"4.892E-13","name":"A1","value":"5e-13","units":"au/d^2","n":1,"desc":"non-gravitational radial acceleration parameter"},{"name":"A2","value":"-2.902e-14","units":"au/d^2","n":2,"desc":"non-gravitational transverse acceleration parameter","title":"non-grav. transverse accel.","kind":"EST","sigma":"1.859E-16"},{"kind":"SET","title":"normalizing factor","sigma":null,"units":null,"value":"1.","name":"ALN","desc":"normalizing factor [default 0.1112620426]","n":0},{"sigma":null,"kind":"SET","title":"non-grav. model exp. k","desc":"non-grav. model constant, exponent k [default 4.6142]","n":0,"name":"NK","units":null,"value":"0."},{"units":null,"value":"2.","name":"NM","desc":"non-grav. model constant, exponent m [default 2.15]","n":0,"title":"non-grav. model exp. m","kind":"SET","sigma":null},{"desc":"normalizing distance, au [default 2.808 au]","n":0,"units":"au","value":"1.","name":"R0","sigma":null,"title":"normalizing distance","kind":"SET"}],"elements":[{"name":"e","label":"e","title":"eccentricity","value":"0.191","units":null,"sigma":"1.8e-09"},{"sigma":"1.6e-09","label":"a","name":"a","units":"au","value":"0.922","title":"semi-major axis"},{"sigma":"2.9e-09","name":"q","label":"q","title":"perihelion distance","value":"0.746","units":"au"},{"label":"i","name":"i","value":"3.34","title":"inclination; angle with respect to x-y ecliptic plane","units":"deg","sigma":"9.9e-08"},{"sigma":"3.1e-06","value":"204","title":"longitude of the ascending node","units":"deg","name":"om","label":"node"},{"sigma":"3.3e-06","name":"w","label":"peri","units":"deg","title":"argument of perihelion","value":"127"},{"units":"deg","title":"mean anomaly","value":"175","label":"M","name":"ma","sigma":"5.3e-07"},{"sigma":"7.1e-07","name":"tp","label":"tp","units":"TDB","value":"2461042.919","title":"time of perihelion passage"},{"name":"per","label":"period","value":"324","title":"sidereal orbital period","units":"d","sigma":"8.2e-07"},{"value":"1.11","title":"mean motion","units":"deg/d","name":"n","label":"n","sigma":"2.8e-09"},{"sigma":"1.9e-09","label":"Q","name":"ad","units":"au","value":"1.1","title":"aphelion distance"}],"source":"JPL","n_obs_used":7370,"comment":null,"pe_used":"DE441","t_jup":"6.466","producer":"Davide Farnocchia"}}