{"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":"2026-09-01T20:47:40.103Z","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-28-c","name":"Kepler-28 c","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1429.7358357953392,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":292.1370409,"dec_deg":42.4294835,"epoch_ra_deg":292.353659,"epoch_dec_deg":42.483927,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-28","semi_major_axis_km":11248263.897933,"periapsis_km":null,"mass_kg":1.2302665807650241e+25,"mass_msun":0.00000618719,"constellation":"Cygnus","discovered":"2011","featured":false,"url":"https://spacecatalog.org/object/kepler-28-c","radius_km":11844.1317,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-28","host_v_mag":15.13,"eccentricity":0.017,"uncertainties":{"mass_kg":[3.105527291251517e+24,4.1805175074539655e+24],"radius_km":[267.88020000000006,267.88020000000006],"distance_ly":[15.2331336212605,15.2331336212605],"eccentricity":[0.014,0.023],"host_mass_solar":[0.026,0.026],"host_radius_solar":[0.013,0.013],"host_temperature_k":[74.9,74.9],"semi_major_axis_km":[71806.977936,71806.977936]},"host_mass_solar":0.684,"inclination_deg":89.98,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.664,"planets_in_system":2,"discovery_facility":"Kepler","host_spectral_type":"M0 V","host_temperature_k":4499.3,"orbital_period_days":8.99,"transit_midpoint_bjd":2455008.68418,"equilibrium_temperature_k":509},"designations":[{"catalog":"Exoplanet","designation":"Kepler-28 c"}],"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":"2026-08-30T09:56:50.739Z","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."}