{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.680","julian_year":2026.68,"time":"2026-09-06T08:24:35.464Z","years_from_j2000":26.68,"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":"k2-117-c","name":"K2-117 c","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":331.4792498010807,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":133.8557342,"dec_deg":10.4692176,"epoch_ra_deg":134.219993,"epoch_dec_deg":10.366904,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-117","semi_major_axis_km":7360215.2384399995,"periapsis_km":null,"mass_kg":2.926362255217776e+25,"mass_msun":0.0000147171,"constellation":"Cancer","discovered":"2017","featured":false,"url":"https://spacecatalog.org/object/k2-117-c","radius_km":13138.886,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-117","host_v_mag":14.639,"eccentricity":0.15,"uncertainties":{"radius_km":[765.3720000000001,765.3720000000001],"distance_ly":[1.2133017251062854,1.2198248526606204],"eccentricity":[0.115822,0.178886],"host_mass_solar":[0.01,0.01],"inclination_deg":[0.48,0.36],"host_radius_solar":[0.01,0.01],"host_temperature_k":[53,53],"semi_major_axis_km":[44879.361209999995,44879.361209999995],"orbital_period_days":[0.000455,0.000462],"argument_of_periastron_deg":[61.7988,61.8212]},"host_mass_solar":0.54,"inclination_deg":89.49,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.51,"planets_in_system":2,"discovery_facility":"K2","host_spectral_type":"M1.0 V","host_temperature_k":3778,"orbital_period_days":5.444017,"transit_midpoint_bjd":2457143.5663,"equilibrium_temperature_k":537,"argument_of_periastron_deg":-77.06},"designations":[{"catalog":"Exoplanet","designation":"K2-117 c"},{"catalog":"Host star","designation":"K2-117"}],"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."}