{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.684","julian_year":2026.684,"time":"2026-09-07T16:24:24.513Z","years_from_j2000":26.684,"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":"k2-118-b","name":"K2-118 b","class":"neptune_like_planet","category":"exoplanet","object_type":"Neptune-like planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1049.3168215178612,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":132.1268608,"dec_deg":15.6558964,"epoch_ra_deg":132.502453,"epoch_dec_deg":15.5569,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-118","semi_major_axis_km":36651478.321499996,"periapsis_km":null,"mass_kg":4.174545339586175e+25,"mass_msun":0.0000209944,"constellation":"Cancer","discovered":"2017","featured":false,"url":"https://spacecatalog.org/object/k2-118-b","radius_km":16200.374000000002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-118","host_v_mag":14,"eccentricity":0.2,"uncertainties":{"radius_km":[1275.6200000000001,1466.9630000000002],"distance_ly":[12.265110584038137,12.265110584038137],"eccentricity":[0.159064,0.183774],"host_mass_solar":[0.075645,0.075645],"inclination_deg":[0.12,0.24],"host_radius_solar":[0.043106,0.046686],"host_temperature_k":[127.34,142.64],"semi_major_axis_km":[1196782.9656,1196782.9656],"orbital_period_days":[0.005249,0.005584],"argument_of_periastron_deg":[123.4359,75.8575]},"host_mass_solar":0.756446,"inclination_deg":89.5,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.734626,"planets_in_system":1,"discovery_facility":"K2","host_temperature_k":4726.29,"orbital_period_days":50.92092,"transit_midpoint_bjd":2457160.473,"equilibrium_temperature_k":394.64,"argument_of_periastron_deg":58.67},"designations":[{"catalog":"Exoplanet","designation":"K2-118 b"},{"catalog":"Host star","designation":"K2-118"}],"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."}