{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.664","julian_year":2026.664,"time":"2026-08-31T09:05:27.877Z","years_from_j2000":26.664,"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-138-e","name":"Kepler-138 e","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":218.07598189447984,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":290.3814122,"dec_deg":43.2930645,"epoch_ra_deg":290.592597,"epoch_dec_deg":43.343195,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-138","semi_major_axis_km":26972496.087209996,"periapsis_km":null,"mass_kg":2.568032183150293e+24,"mass_msun":0.0000012915,"constellation":"Lyra","discovered":"2022","featured":false,"url":"https://spacecatalog.org/object/kepler-138-e","radius_km":5083.345700000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-138","host_v_mag":13.04,"eccentricity":0.112,"uncertainties":{"mass_kg":[5.972167867791379e+23,1.2541552522361896e+24],"distance_ly":[0.34898732415691547,0.34898732415691547],"eccentricity":[0.024,0.018],"host_mass_solar":[0.012,0.012],"inclination_deg":[1,1],"host_radius_solar":[0.014,0.013],"host_temperature_k":[51,50],"semi_major_axis_km":[209437.01898,209437.01898],"orbital_period_days":[0.006,0.006],"argument_of_periastron_deg":[14,10]},"host_mass_solar":0.535,"inclination_deg":88.53,"stars_in_system":1,"discovery_method":"Transit Timing Variations","host_radius_solar":0.535,"planets_in_system":4,"discovery_facility":"Multiple Observatories","host_spectral_type":"M1 V","host_temperature_k":3841,"orbital_period_days":38.23,"periastron_epoch_bjd":2454924.1,"equilibrium_temperature_k":292,"argument_of_periastron_deg":76},"designations":[{"catalog":"Exoplanet","designation":"Kepler-138 e"}],"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."}