{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.684","julian_year":2026.684,"time":"2026-09-07T16:51:46.582Z","years_from_j2000":26.684,"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-217958-b","name":"HD 217958 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":201.5506167047056,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":346.136577,"dec_deg":-25.6917758,"epoch_ra_deg":346.498881,"epoch_dec_deg":-25.546982,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 217958","semi_major_axis_km":562188798.0906,"periapsis_km":null,"mass_kg":9.94617290284466e+26,"mass_msun":0.000500207,"constellation":"Piscis Austrinus","discovered":"2022","featured":false,"url":"https://spacecatalog.org/object/hd-217958-b","radius_km":90569.02,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 217958","host_v_mag":8.05,"eccentricity":0.156,"uncertainties":{"mass_kg":[1.1958184977870122e+26,6.586492361215543e+26],"distance_ly":[0.6803622039171268,0.6846022368274445],"eccentricity":[0.081,0.093],"host_mass_solar":[0.141,0.141],"inclination_deg":[38.771,31.078],"host_radius_solar":[0.075236,0.060683],"host_temperature_k":[161.07,108.9],"semi_major_axis_km":[29919574.14,25282040.1483],"orbital_period_days":[91.15204,66.52293],"argument_of_periastron_deg":[117.42,81.413]},"host_mass_solar":1.08,"inclination_deg":91.357,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":1.32619,"planets_in_system":1,"discovery_facility":"Multiple Observatories","host_temperature_k":5930.64,"orbital_period_days":2560.19774,"periastron_epoch_bjd":2450608.775,"equilibrium_temperature_k":169.89,"argument_of_periastron_deg":252.258},"designations":[{"catalog":"Exoplanet","designation":"HD 217958 b"},{"catalog":"Host star","designation":"HD 217958"}],"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."}