{"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":"2026-08-27T17:05:53.003Z","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":"75-cet-c","name":"75 Cet c","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":270.58357098672064,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":38.0391598,"dec_deg":-1.0350269,"epoch_ra_deg":38.38156,"epoch_dec_deg":-0.916173,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"75 Cet","semi_major_axis_km":587770033.9803,"periapsis_km":null,"mass_kg":1.7310896349542406e+27,"mass_msun":0.00087059,"constellation":"Cetus","discovered":"2023","featured":false,"url":"https://spacecatalog.org/object/75-cet-c","radius_km":88655.59000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"75 Cet","host_v_mag":5.3532,"eccentricity":0.023,"uncertainties":{"mass_kg":[2.714318177592389e+26,1.6703496480248008e+26],"distance_ly":[2.360230627347214,2.360230627347214],"eccentricity":[0.003,0.191],"host_mass_solar":[0.08,0.07],"host_radius_solar":[0.26,0.15],"semi_major_axis_km":[7779089.276399999,8676676.500599999],"orbital_period_days":[40.47,45.98],"argument_of_periastron_deg":[51,156.8]},"host_mass_solar":1.92,"stars_in_system":2,"discovery_method":"Radial Velocity","host_radius_solar":10.38,"planets_in_system":2,"discovery_facility":"Okayama Astrophysical Observatory","host_spectral_type":"G3 III","host_temperature_k":4809,"orbital_period_days":2051.62,"periastron_epoch_bjd":2454284.9,"equilibrium_temperature_k":376.92,"argument_of_periastron_deg":123},"designations":[{"catalog":"Exoplanet","designation":"75 Cet c"},{"catalog":"Host star","designation":"75 Cet"}],"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."}