{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.688","julian_year":2026.688,"time":"2026-09-09T02:54:29.372Z","years_from_j2000":26.688,"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":"bet-umi-b","name":"β 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":126.46622222180966,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":222.676495,"dec_deg":74.155548,"epoch_ra_deg":222.67082,"epoch_dec_deg":74.04398,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"β UMi","semi_major_axis_km":209437018.97999996,"periapsis_km":null,"mass_kg":1.1578241845287147e+28,"mass_msun":0.00582286,"constellation":"Ursa Minor","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/bet-umi-b","radius_km":81001.87,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"β UMi","host_v_mag":2.0569,"eccentricity":0.19,"uncertainties":{"mass_kg":[1.8979549483841003e+27,1.8979549483841003e+27],"distance_ly":[2.5499199150634944,2.5499199150634944],"eccentricity":[0.02,0.02],"host_mass_solar":[0.2,0.2],"host_radius_solar":[1.1,1.1],"host_temperature_k":[25,25],"semi_major_axis_km":[14959787.07,14959787.07],"orbital_period_days":[2.7,2.7],"argument_of_periastron_deg":[2.8,2.8]},"host_mass_solar":1.4,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":38.3,"planets_in_system":1,"discovery_facility":"Bohyunsan Optical Astronomical Observatory","host_spectral_type":"K4 III","host_temperature_k":4126,"orbital_period_days":522.3,"periastron_epoch_bjd":2453175.3,"equilibrium_temperature_k":1040.63,"argument_of_periastron_deg":307.4},"designations":[{"catalog":"Exoplanet","designation":"bet UMi b"},{"catalog":"Host star","designation":"bet 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."}