{"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":"2026-09-07T21:38:57.328Z","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-220842-b","name":"HD 220842 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":210.85944588111917,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":351.6534162,"dec_deg":56.8871415,"epoch_ra_deg":351.961404,"epoch_dec_deg":57.034873,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 220842","semi_major_axis_km":110702424.31799999,"periapsis_km":null,"mass_kg":6.036066480676026e+27,"mass_msun":0.00303562,"constellation":"Cassiopeia","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/hd-220842-b","radius_km":83553.11,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 220842","host_v_mag":7.98,"eccentricity":0.404,"uncertainties":{"mass_kg":[2.8472011701302012e+26,2.8472011701302012e+26],"distance_ly":[0.5443549944092447,0.5472904018086955],"eccentricity":[0.009,0.009],"host_mass_solar":[0.06,0.06],"host_radius_solar":[0.027026,0.036777],"host_temperature_k":[20,20],"semi_major_axis_km":[2692761.6725999997,2692761.6725999997],"orbital_period_days":[0.19,0.19],"argument_of_periastron_deg":[1.7,1.7]},"host_mass_solar":1.13,"stars_in_system":2,"discovery_method":"Radial Velocity","host_radius_solar":1.41647,"planets_in_system":1,"discovery_facility":"Haute-Provence Observatory","host_spectral_type":"F8","host_temperature_k":5960,"orbital_period_days":218.47,"periastron_epoch_bjd":2456624.8,"equilibrium_temperature_k":397.62,"argument_of_periastron_deg":-134.9},"designations":[{"catalog":"Exoplanet","designation":"HD 220842 b"},{"catalog":"Host star","designation":"HD 220842"}],"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."}