{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T14:30:18.942Z","years_from_j2000":26.678,"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":"hd-50554-b","name":"HD 50554 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":101.65120130471112,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":103.678273,"dec_deg":24.2451409,"epoch_ra_deg":104.088006,"epoch_dec_deg":24.211482,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 50554","semi_major_axis_km":352003789.7571,"periapsis_km":null,"mass_kg":1.1104028908576817e+28,"mass_msun":0.00558438,"constellation":"Gemini","discovered":"2002","featured":false,"url":"https://spacecatalog.org/object/hd-50554-b","radius_km":81639.68000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 50554","host_v_mag":6.8561,"eccentricity":0.501,"uncertainties":{"mass_kg":[9.870247918734947e+26,1.7083121397810487e+27],"distance_ly":[0.18069063325507584,0.18134294601050932],"eccentricity":[0.03,0.03],"host_mass_solar":[0.01,0.01],"inclination_deg":[12,12],"host_radius_solar":[0.02,0.02],"host_temperature_k":[70,70],"semi_major_axis_km":[6761823.755639999,6761823.755639999],"orbital_period_days":[37,37],"argument_of_periastron_deg":[2.2,2.1]},"host_mass_solar":1.04,"inclination_deg":61,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":1.02,"planets_in_system":1,"discovery_facility":"Lick Observatory","host_spectral_type":"F8 V","host_temperature_k":5987,"orbital_period_days":1293,"periastron_epoch_bjd":2451832.4,"transit_midpoint_bjd":2453200.5,"equilibrium_temperature_k":190.08,"argument_of_periastron_deg":3.5},"designations":[{"catalog":"Exoplanet","designation":"HD 50554 b"},{"catalog":"Host star","designation":"HD 50554"}],"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."}