{"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":"2026-09-01T18:48:39.270Z","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":"k2-239-d","name":"K2-239 d","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":101.38538385687198,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":160.5941265,"dec_deg":4.4413751,"epoch_ra_deg":160.942047,"epoch_dec_deg":4.301014,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-239","semi_major_axis_km":10247454.14295,"periapsis_km":null,"mass_kg":8.181869978874191e+24,"mass_msun":0.00000411478,"constellation":"Sextans","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-239-d","radius_km":7015.910000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-239","host_v_mag":14.632,"uncertainties":{"radius_km":[637.8100000000001,637.8100000000001],"distance_ly":[0.2694051679940301,0.27103594988261376],"host_mass_solar":[0.01,0.01],"inclination_deg":[0.45,0.38],"host_radius_solar":[0.01,0.01],"host_temperature_k":[18,18],"semi_major_axis_km":[179517.44483999998,179517.44483999998],"orbital_period_days":[0.001,0.001]},"host_mass_solar":0.4,"inclination_deg":89.43,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.36,"planets_in_system":3,"discovery_facility":"K2","host_spectral_type":"M3.0 V","host_temperature_k":3420,"orbital_period_days":10.115,"transit_midpoint_bjd":2457908.381,"equilibrium_temperature_k":399},"designations":[{"catalog":"Exoplanet","designation":"K2-239 d"},{"catalog":"Host star","designation":"K2-239"}],"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."}