{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T23:36:25.543Z","years_from_j2000":26.673,"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":"k2-157-b","name":"K2-157 b","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":973.1625688847788,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":183.7514959,"dec_deg":-5.7820178,"epoch_ra_deg":184.096383,"epoch_dec_deg":-5.931324,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-157","semi_major_axis_km":1439131.516134,"periapsis_km":null,"mass_kg":6.808271369282171e+24,"mass_msun":0.00000342398,"constellation":"Virgo","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-157-b","radius_km":5963.5235,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-157","host_v_mag":12.942,"uncertainties":{"mass_kg":[2.5083105044723793e+24,2.4485888257944655e+24],"radius_km":[574.029,574.029],"distance_ly":[14.53026662728092,14.970577737198523],"host_mass_solar":[0.029,0.029],"inclination_deg":[9.1,9.3],"host_radius_solar":[0.019,0.019],"host_temperature_k":[64,64],"semi_major_axis_km":[14959.78707,14959.78707],"orbital_period_days":[0.0000088,0.0000078]},"host_mass_solar":0.89,"inclination_deg":89.2,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.86,"planets_in_system":3,"discovery_facility":"K2","host_spectral_type":"G9 V","host_temperature_k":5334,"orbital_period_days":0.3652575,"transit_midpoint_bjd":2457582.822,"equilibrium_temperature_k":2432},"designations":[{"catalog":"Exoplanet","designation":"K2-157 b"}],"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."}