{"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":"2026-09-07T02:33:47.035Z","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":"16-cyg-b-b","name":"16 Cyg B b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":68.94847978018642,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":295.4656422,"dec_deg":50.5168243,"epoch_ra_deg":295.644701,"epoch_dec_deg":50.579274,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"16 Cyg B","semi_major_axis_km":248332465.36199996,"periapsis_km":null,"mass_kg":3.3786787218878385e+27,"mass_msun":0.00169919,"constellation":"Cygnus","discovered":"1996","featured":false,"url":"https://spacecatalog.org/object/16-cyg-b-b","radius_km":86104.35,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"16 Cyg B","host_v_mag":6.215,"eccentricity":0.68,"uncertainties":{"mass_kg":[1.5185072907361073e+26,1.5185072907361073e+26],"distance_ly":[0.03620335792655852,0.035877201548841775],"eccentricity":[0.02,0.02],"host_mass_solar":[0.04,0.04],"host_radius_solar":[0.01,0.01],"host_temperature_k":[8,8],"semi_major_axis_km":[4487936.120999999,4487936.120999999],"orbital_period_days":[1,1],"argument_of_periastron_deg":[0.6,0.6]},"host_mass_solar":1.08,"stars_in_system":3,"discovery_method":"Radial Velocity","host_radius_solar":1.13,"planets_in_system":1,"discovery_facility":"Multiple Observatories","host_spectral_type":"G3 V","host_temperature_k":5750,"orbital_period_days":798.5,"periastron_epoch_bjd":2450539.3,"transit_midpoint_bjd":2456937.32,"equilibrium_temperature_k":228.76,"argument_of_periastron_deg":82.74},"designations":[{"catalog":"Exoplanet","designation":"16 Cyg B b"},{"catalog":"Host star","designation":"16 Cyg B"}],"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."}