{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.667","julian_year":2026.667,"time":"2026-09-01T17:02:45.566Z","years_from_j2000":26.667,"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-304-e","name":"Kepler-304 e","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1417.749588914249,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":294.4418031,"dec_deg":40.5575408,"epoch_ra_deg":294.668499,"epoch_dec_deg":40.617549,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-304","semi_major_axis_km":3466182.6641189996,"periapsis_km":null,"mass_kg":1.116795391276988e+25,"mass_msun":0.00000561653,"constellation":"Cygnus","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/kepler-304-e","radius_km":7653.72,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-304","host_v_mag":15.065,"eccentricity":0,"uncertainties":{"radius_km":[191.34300000000002,382.68600000000004],"distance_ly":[16.8655462917328,17.269980200101564],"host_mass_solar":[0.026,0.02],"host_radius_solar":[0.017,0.013],"host_temperature_k":[46.95,68.1],"semi_major_axis_km":[14959.78707,14959.78707],"orbital_period_days":[0.000002797,0.000002797]},"host_mass_solar":0.8,"inclination_deg":87.54,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.73,"planets_in_system":4,"discovery_facility":"Kepler","host_temperature_k":4817,"orbital_period_days":1.499146953,"transit_midpoint_bjd":2454966.06857,"equilibrium_temperature_k":1137},"designations":[{"catalog":"Exoplanet","designation":"Kepler-304 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."}