{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-03T06:18:56.891Z","years_from_j2000":26.671,"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-231-b","name":"Kepler-231 b","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1032.6697999991986,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":293.9733913,"dec_deg":50.531846,"epoch_ra_deg":294.150347,"epoch_dec_deg":50.590697,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-231","semi_major_axis_km":11070242.431799999,"periapsis_km":null,"mass_kg":2.114147425198148e+26,"mass_msun":0.000106324,"constellation":"Cygnus","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-231-b","radius_km":11034.113000000001,"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-231","host_v_mag":15.813,"eccentricity":0,"uncertainties":{"mass_kg":[9.91379866053369e+25,1.1765170699549017e+26],"radius_km":[765.3720000000001,765.3720000000001],"distance_ly":[10.701190752886353,10.919715525956569],"host_mass_solar":[0.014,0.014],"host_radius_solar":[0.021,0.021],"host_temperature_k":[150,150],"orbital_period_days":[0.000027,0.000027]},"host_mass_solar":0.58,"inclination_deg":89.22,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.49,"planets_in_system":2,"discovery_facility":"Kepler","host_spectral_type":"M1 V","host_temperature_k":3767,"orbital_period_days":10.065275,"transit_midpoint_bjd":2454969.28185,"equilibrium_temperature_k":488},"designations":[{"catalog":"Exoplanet","designation":"Kepler-231 b"}],"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."}