{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.654","julian_year":2026.654,"time":"2026-08-27T17:48:15.874Z","years_from_j2000":26.654,"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":"47-uma-c","name":"47 UMa c","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":44.998816964445936,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":164.8647611,"dec_deg":40.4304931,"epoch_ra_deg":165.243357,"epoch_dec_deg":40.286701,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"47 UMa","semi_major_axis_km":538552334.52,"periapsis_km":null,"mass_kg":1.0249494216382243e+27,"mass_msun":0.000515462,"constellation":"Ursa Major","discovered":"2001","featured":false,"url":"https://spacecatalog.org/object/47-uma-c","radius_km":90569.02,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"47 UMa","host_v_mag":5.03352,"eccentricity":0.098,"uncertainties":{"mass_kg":[1.385602667006278e+26,1.2527219319479197e+26],"distance_ly":[0.09425919316013884,0.09425919316013884],"eccentricity":[0.096,0.047],"host_mass_solar":[0.137608,0.128402],"host_radius_solar":[0.058353,0.038883],"host_temperature_k":[113.53,92.94],"semi_major_axis_km":[14959787.07,14959787.07],"orbital_period_days":[87,100],"argument_of_periastron_deg":[160,114]},"host_mass_solar":1.06,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":1.21334,"planets_in_system":3,"discovery_facility":"Lick Observatory","host_spectral_type":"G0V","host_temperature_k":5872,"orbital_period_days":2391,"periastron_epoch_bjd":2452441,"transit_midpoint_bjd":2455651,"equilibrium_temperature_k":164.38,"argument_of_periastron_deg":295},"designations":[{"catalog":"Exoplanet","designation":"47 UMa c"},{"catalog":"Host star","designation":"47 UMa"}],"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":"2026-08-27T16:03:54.983Z","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."}