{"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":"2026-09-04T05:15:47.611Z","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-338-b","name":"Kepler-338 b","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":1802.9859328906032,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":282.9790593,"dec_deg":40.7844188,"epoch_ra_deg":283.196997,"epoch_dec_deg":40.816042,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-338","semi_major_axis_km":17502950.8719,"periapsis_km":null,"mass_kg":1.827483367544162e+26,"mass_msun":0.0000919068,"constellation":"Lyra","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-338-b","radius_km":15562.564,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-338","host_v_mag":12.19,"eccentricity":0.04,"uncertainties":{"mass_kg":[1.260127420103981e+26,1.4452646240055137e+26],"radius_km":[829.153,829.153],"distance_ly":[21.666568171723263,22.188418376070054],"eccentricity":[0.04,0.27],"host_mass_solar":[0.021,0.026],"host_radius_solar":[0.082,0.082],"host_temperature_k":[77,77],"orbital_period_days":[0.000059,0.000059]},"host_mass_solar":1.105,"inclination_deg":89.9,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.735,"planets_in_system":4,"discovery_facility":"Kepler","host_temperature_k":5923,"orbital_period_days":13.726976,"transit_midpoint_bjd":2454971.74833,"equilibrium_temperature_k":1005},"designations":[{"catalog":"Exoplanet","designation":"Kepler-338 b"},{"catalog":"Host star","designation":"Kepler-338"}],"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."}