{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.674","julian_year":2026.674,"time":"2026-09-04T03:36:09.691Z","years_from_j2000":26.674,"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-1391-b","name":"Kepler-1391 b","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":3386.644748021805,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":294.8309749,"dec_deg":46.6595768,"epoch_ra_deg":295.030215,"epoch_dec_deg":46.720518,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-1391","semi_major_axis_km":44946680.251815,"periapsis_km":null,"mass_kg":2.066370082255817e+25,"mass_msun":0.0000103921,"constellation":"Cygnus","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/kepler-1391-b","radius_km":10715.208,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-1391","host_v_mag":13.906,"eccentricity":0,"uncertainties":{"radius_km":[1148.058,1658.306],"distance_ly":[57.256752108174304,57.256752108174304],"host_mass_solar":[0.041,0.047],"host_radius_solar":[0.109,0.166],"host_temperature_k":[77.55,90.4],"semi_major_axis_km":[577447.780902,577447.780902],"orbital_period_days":[0.0005236,0.0005236]},"host_mass_solar":1.03,"inclination_deg":89.8,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.1,"planets_in_system":1,"discovery_facility":"Kepler","host_temperature_k":5840,"orbital_period_days":54.4092333,"transit_midpoint_bjd":2455008.40209,"equilibrium_temperature_k":513},"designations":[{"catalog":"Exoplanet","designation":"Kepler-1391 b"},{"catalog":"Host star","designation":"Kepler-1391"}],"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."}