{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.681","julian_year":2026.681,"time":"2026-09-06T20:40:39.699Z","years_from_j2000":26.681,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued J2000 position is carried along the great circle the object's own published motion puts it on, at a constant velocity, and the result is referred to the true equator and equinox of this instant. Those are separate things: the motion moves the object, and the rotation turns the grid under it by about fifty arcseconds a year, with nutation adding up to another seventeen.","excluded":"Parallax, the radial-velocity perspective term, aberration and refraction; each is below the accuracy of the catalogued positions themselves. An object with no published proper motion comes back where the catalogue has it rather than at a fabricated zero, and says so with a null pm_ra_mas_yr. A body with no fixed position is not propagated at all — its place comes from an ephemeris, which is what /api/v1/visible answers with."},"slug":"xo-3-b","name":"XO-3 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":694.8859474168534,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":65.4695814,"dec_deg":57.8172095,"epoch_ra_deg":66.029267,"epoch_dec_deg":57.880733,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"XO-3","semi_major_axis_km":7203137.474204999,"periapsis_km":null,"mass_kg":2.5188113438771685e+28,"mass_msun":0.0126675,"constellation":"Camelopardalis","discovered":"2007","featured":false,"url":"https://spacecatalog.org/object/xo-3-b","radius_km":94369.43971401201,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"XO-3","host_v_mag":9.854,"eccentricity":0.2791,"uncertainties":{"mass_kg":[6.833248559124195e+26,6.643436099148523e+26],"radius_km":[1787.300011012,1787.300011012],"distance_ly":[8.66923651971104,8.88449972900409],"eccentricity":[0.0022,0.0024],"host_mass_solar":[0.058,0.056],"inclination_deg":[0.17,0.17],"host_radius_solar":[0.027,0.027],"host_temperature_k":[100,110],"semi_major_axis_km":[97238.61595499999,91254.701127],"orbital_period_days":[1.4e-7,1.4e-7],"argument_of_periastron_deg":[0.84,0.77]},"host_mass_solar":1.449,"inclination_deg":83.66,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.523,"planets_in_system":1,"discovery_facility":"XO","host_spectral_type":"F5V","host_temperature_k":6970,"orbital_period_days":3.19152309,"periastron_epoch_bjd":2454024.7278,"transit_midpoint_bjd":2457424.98786,"equilibrium_temperature_k":1890,"argument_of_periastron_deg":-10.84},"designations":[{"catalog":"Exoplanet","designation":"XO-3 b"},{"catalog":"Host star","designation":"XO-3"}],"source":{"id":"exoplanet_archive","name":"NASA Exoplanet Archive (Planetary Systems Composite Parameters)","url":"https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=PSCompPars","license":"Public domain (NASA)"},"updated_at":"2026-09-02T19:50:56.720Z","attribution":"Data from SpaceCatalog.org. Individual records carry their source and license in `source`; attribution is required for CC-BY and CC-BY-SA rows."}