{"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":"2026-09-01T14:31:01.417Z","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":"k2-252-b","name":"K2-252 b","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":746.3729932032185,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":182.3663818,"dec_deg":-8.3096141,"epoch_ra_deg":182.711003,"epoch_dec_deg":-8.459032,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-252","semi_major_axis_km":15573138.339869998,"periapsis_km":null,"mass_kg":2.1977577753472276e+25,"mass_msun":0.0000110528,"constellation":"Virgo","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-252-b","radius_km":11097.894,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-252","host_v_mag":12.93,"uncertainties":{"radius_km":[765.3720000000001,1084.277],"distance_ly":[6.676421051861738,6.793837347839766],"host_mass_solar":[0.01,0.02],"host_radius_solar":[0.01,0.01],"host_temperature_k":[39,41],"semi_major_axis_km":[104718.50949,119678.29656],"orbital_period_days":[0.00448,0.00461]},"host_mass_solar":0.79,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.82,"planets_in_system":1,"discovery_facility":"K2","host_temperature_k":5152,"orbital_period_days":13.81513,"transit_midpoint_bjd":2457596.1901,"equilibrium_temperature_k":639},"designations":[{"catalog":"Exoplanet","designation":"K2-252 b"},{"catalog":"Host star","designation":"K2-252"}],"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."}