{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.676","julian_year":2026.676,"time":"2026-09-04T19:43:44.069Z","years_from_j2000":26.676,"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":"k2-238-b","name":"K2-238 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1754.6006342563244,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":347.7043164,"dec_deg":-7.8575592,"epoch_ra_deg":348.05303,"epoch_dec_deg":-7.711855,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-238","semi_major_axis_km":6881502.052199999,"periapsis_km":null,"mass_kg":1.6323953375413152e+27,"mass_msun":0.000820955,"constellation":"Aquarius","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-238-b","radius_km":92939.75977,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-238","host_v_mag":13.973,"eccentricity":0,"uncertainties":{"mass_kg":[2.277760936104161e+26,2.4675743474461742e+26],"radius_km":[10008.897206000001,10723.818435],"host_mass_solar":[0.08,0.08],"inclination_deg":[1.5,1.8],"host_radius_solar":[0.16,0.16],"host_temperature_k":[78,78],"semi_major_axis_km":[897587.2241999999,1047185.0948999999],"orbital_period_days":[0.00003,0.00003]},"host_mass_solar":1.19,"inclination_deg":84.5,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.59,"planets_in_system":1,"discovery_facility":"K2","host_spectral_type":"G2 V","host_temperature_k":5630,"orbital_period_days":3.20466,"transit_midpoint_bjd":2457740.5036,"equilibrium_temperature_k":1587,"argument_of_periastron_deg":90},"designations":[{"catalog":"Exoplanet","designation":"K2-238 b"},{"catalog":"Host star","designation":"K2-238"}],"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."}