{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.686","julian_year":2026.686,"time":"2026-09-08T16:18:42.944Z","years_from_j2000":26.686,"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-99283-b","name":"HD 99283 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":362.3369046968618,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":171.4874082,"dec_deg":55.8506653,"epoch_ra_deg":171.866914,"epoch_dec_deg":55.702977,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 99283","semi_major_axis_km":161565700.356,"periapsis_km":null,"mass_kg":1.8411808617640188e+27,"mass_msun":0.000925956,"constellation":"Ursa Major","discovered":"2021","featured":false,"url":"https://spacecatalog.org/object/hd-99283-b","radius_km":88017.78000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 99283","host_v_mag":5.72916,"eccentricity":0.2,"uncertainties":{"mass_kg":[4.745311499391802e+26,1.1388747598540324e+26],"distance_ly":[2.315710281788878,2.3450643557833852],"eccentricity":[0.146,0.102],"host_mass_solar":[0.3,0.31],"host_radius_solar":[0.39,0.66],"semi_major_axis_km":[10471850.949000001,7479893.535],"orbital_period_days":[1.7,5.2],"argument_of_periastron_deg":[41,62]},"host_mass_solar":1.76,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":11.21,"planets_in_system":1,"discovery_facility":"Okayama Astrophysical Observatory","host_spectral_type":"K0 III","host_temperature_k":4886,"orbital_period_days":310.4,"periastron_epoch_bjd":2455291.1,"equilibrium_temperature_k":759.06,"argument_of_periastron_deg":291},"designations":[{"catalog":"Exoplanet","designation":"HD 99283 b"},{"catalog":"Host star","designation":"HD 99283"}],"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."}