{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T18:05:52.388Z","years_from_j2000":26.673,"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-54-d","name":"Kepler-54 d","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":886.1701398201691,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":294.7739245,"dec_deg":43.0561976,"epoch_ra_deg":294.990233,"epoch_dec_deg":43.117017,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-54","semi_major_axis_km":18849331.7082,"periapsis_km":null,"mass_kg":7.223098149378962e+25,"mass_msun":0.000036326,"constellation":"Cygnus","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-54-d","radius_km":9758.493,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-54","host_v_mag":16.282,"eccentricity":0,"uncertainties":{"radius_km":[510.24800000000005,510.24800000000005],"distance_ly":[9.515612319885989,9.515612319885989],"host_mass_solar":[0.013,0.013],"host_radius_solar":[0.021,0.021],"host_temperature_k":[100,100],"orbital_period_days":[0.000143,0.000143]},"host_mass_solar":0.518,"inclination_deg":89.79,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.554,"planets_in_system":3,"discovery_facility":"Kepler","host_spectral_type":"M1 V","host_temperature_k":4252,"orbital_period_days":20.995694,"transit_midpoint_bjd":2454985.31995,"equilibrium_temperature_k":328},"designations":[{"catalog":"Exoplanet","designation":"Kepler-54 d"},{"catalog":"Host star","designation":"Kepler-54"}],"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."}