{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T19:30:15.701Z","years_from_j2000":26.67,"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-450-d","name":"Kepler-450 d","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1487.2143742403612,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":295.4865821,"dec_deg":51.0135237,"epoch_ra_deg":295.662604,"epoch_dec_deg":51.075975,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-450","semi_major_axis_km":12371743.90689,"periapsis_km":null,"mass_kg":1.0511015447312827e+26,"mass_msun":0.0000528614,"constellation":"Cygnus","discovered":"2015","featured":false,"url":"https://spacecatalog.org/object/kepler-450-d","radius_km":5338.4697,"radius_kind":null,"data_quality":"The published mass and radius imply a density no material has. One of the two is likely an upper limit rather than a measurement.","description":null,"properties":{"host_star":"Kepler-450","host_v_mag":11.991,"eccentricity":0.14,"uncertainties":{"mass_kg":[4.001352471420224e+25,5.6735594744018105e+25],"radius_km":[433.71080000000006,433.71080000000006],"distance_ly":[16.54917460534756,16.924254439721818],"eccentricity":[0.14,0.24],"host_mass_solar":[0.142064,0.197747],"host_radius_solar":[0.106909,0.080191],"host_temperature_k":[187.39,130.15],"semi_major_axis_km":[70310.999229,70310.999229],"orbital_period_days":[0.00023,0.00023]},"host_mass_solar":1.19,"inclination_deg":87.91,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.64162,"planets_in_system":3,"discovery_facility":"Kepler","host_temperature_k":6197.21,"orbital_period_days":7.51464,"transit_midpoint_bjd":2454969.17528,"equilibrium_temperature_k":1199},"designations":[{"catalog":"Exoplanet","designation":"Kepler-450 d"},{"catalog":"Host star","designation":"Kepler-450"}],"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":"2026-09-02T18:38:07.546Z","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."}