{"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":"2026-09-07T00:09:19.103Z","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":"8-umi-b","name":"8 UMi b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":530.1737151061208,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":224.201685,"dec_deg":74.9009379,"epoch_ra_deg":224.167075,"epoch_dec_deg":74.792081,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"8 UMi","semi_major_axis_km":69114216.2634,"periapsis_km":null,"mass_kg":3.131905589598589e+27,"mass_msun":0.00157508,"constellation":"Ursa Minor","discovered":"2015","featured":false,"url":"https://spacecatalog.org/object/8-umi-b","radius_km":86104.35,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"8 UMi","host_v_mag":6.83295,"eccentricity":0.062,"uncertainties":{"mass_kg":[1.1388747598540324e+26,1.1388747598540324e+26],"distance_ly":[2.1069702000501627,2.123278018936],"eccentricity":[0.03,0.028],"host_mass_solar":[0.06,0.06],"host_radius_solar":[0.14,0.14],"host_temperature_k":[100,100],"semi_major_axis_km":[897587.2241999999,897587.2241999999],"orbital_period_days":[0.06,0.06],"argument_of_periastron_deg":[26.5,30.5]},"host_mass_solar":1.51,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":10.73,"planets_in_system":1,"discovery_facility":"Bohyunsan Optical Astronomical Observatory","host_spectral_type":"K0","host_temperature_k":4847,"orbital_period_days":93.31,"periastron_epoch_bjd":2457601.379,"equilibrium_temperature_k":1126.38,"argument_of_periastron_deg":54},"designations":[{"catalog":"Exoplanet","designation":"8 UMi b"},{"catalog":"Host star","designation":"8 UMi"}],"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."}