{"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":"2026-09-02T03:31:28.633Z","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-238-d","name":"Kepler-238 d","class":"neptune_like_planet","category":"exoplanet","object_type":"Neptune-like planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":5866.737844179922,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":287.8971066,"dec_deg":40.6378141,"epoch_ra_deg":288.118401,"epoch_dec_deg":40.681826,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-238","semi_major_axis_km":17203755.1305,"periapsis_km":null,"mass_kg":1.3795707774598087e+26,"mass_msun":0.0000693806,"constellation":"Lyra","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-238-d","radius_km":19580.767,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-238","host_v_mag":15.297,"eccentricity":0,"uncertainties":{"mass_kg":[3.643022399352741e+25,4.71801261555519e+25],"radius_km":[3635.517,3635.517],"distance_ly":[226.71129815090836,245.3022116807627],"host_mass_solar":[0.062,0.035],"host_radius_solar":[0.264,0.264],"host_temperature_k":[100,100],"orbital_period_days":[0.000081,0.000081]},"host_mass_solar":1.229,"inclination_deg":89.95,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.43,"planets_in_system":5,"discovery_facility":"Kepler","host_temperature_k":5751,"orbital_period_days":13.233549,"transit_midpoint_bjd":2454973.32179,"equilibrium_temperature_k":888},"designations":[{"catalog":"Exoplanet","designation":"Kepler-238 d"}],"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":"2026-09-01T22:58:55.274Z","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."}