{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.668","julian_year":2026.668,"time":"2026-09-02T01:22:58.051Z","years_from_j2000":26.668,"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":"kepler-16-b","name":"Kepler-16 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":244.89516852137223,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":289.0758307,"dec_deg":51.757229,"epoch_ra_deg":289.23957,"epoch_dec_deg":51.804098,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-16","semi_major_axis_km":105436579.26935999,"periapsis_km":null,"mass_kg":6.32052441951965e+26,"mass_msun":0.000317868,"constellation":"Cygnus","discovered":"2011","featured":false,"url":"https://spacecatalog.org/object/kepler-16-b","radius_km":53890.48033,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-16","host_v_mag":12.144,"eccentricity":0.0069,"uncertainties":{"mass_kg":[3.0368473607719163e+25,3.0368473607719163e+25],"radius_km":[185.60271000000003,185.60271000000003],"distance_ly":[0.5009761961729179,0.5026069780615016],"eccentricity":[0.0015,0.001],"host_mass_solar":[0.0034,0.0035],"inclination_deg":[0.0023,0.0022],"host_radius_solar":[0.0013,0.0013],"host_temperature_k":[150,150],"semi_major_axis_km":[164557.65777,164557.65777],"orbital_period_days":[0.037,0.02],"argument_of_periastron_deg":[22,10]},"host_mass_solar":0.6897,"inclination_deg":90.0322,"stars_in_system":2,"discovery_method":"Transit","host_radius_solar":0.6489,"planets_in_system":1,"discovery_facility":"Kepler","host_temperature_k":4450,"orbital_period_days":228.776,"periastron_epoch_bjd":2457535,"transit_midpoint_bjd":2455212.12316,"equilibrium_temperature_k":205.9,"argument_of_periastron_deg":318},"designations":[{"catalog":"Exoplanet","designation":"Kepler-16 b"},{"catalog":"Host star","designation":"Kepler-16"}],"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":"2026-09-01T22:58:55.274Z","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."}