{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.682","julian_year":2026.682,"time":"2026-09-07T06:28:04.364Z","years_from_j2000":26.682,"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":"gaia-4-b","name":"Gaia-4 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":239.66916488121686,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":209.5063762,"dec_deg":31.6954898,"epoch_ra_deg":209.806267,"epoch_dec_deg":31.564371,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Gaia-4","semi_major_axis_km":null,"periapsis_km":null,"mass_kg":2.2397870277129306e+28,"mass_msun":0.0112642,"constellation":"Canes Venatici","discovered":"2025","featured":false,"url":"https://spacecatalog.org/object/gaia-4-b","radius_km":79088.44,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Gaia-4","host_v_mag":12.405,"eccentricity":0.338,"uncertainties":{"mass_kg":[1.2527622358394356e+27,1.385630957822406e+27],"distance_ly":[0.49869310152890073,0.5009761961729179],"eccentricity":[0.023,0.026],"host_mass_solar":[0.023,0.025],"inclination_deg":[4.4,4.2],"host_radius_solar":[0.015,0.014],"host_temperature_k":[77,77],"orbital_period_days":[1.3,1.4],"argument_of_periastron_deg":[4.8,5.5]},"host_mass_solar":0.644,"inclination_deg":116.9,"stars_in_system":1,"discovery_method":"Astrometry","host_radius_solar":0.624,"planets_in_system":1,"discovery_facility":"European Space Agency (ESA) Gaia Satellite","host_temperature_k":4034,"orbital_period_days":571.3,"periastron_epoch_bjd":2457386.1,"argument_of_periastron_deg":180.3},"designations":[{"catalog":"Exoplanet","designation":"Gaia-4 b"},{"catalog":"Host star","designation":"Gaia-4"}],"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."}