{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.680","julian_year":2026.68,"time":"2026-09-06T06:05:46.245Z","years_from_j2000":26.68,"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":"alf-ari-b","name":"α Ari b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":65.91682363367151,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":31.793286,"dec_deg":23.462421,"epoch_ra_deg":32.171119,"epoch_dec_deg":23.590487,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"α Ari","semi_major_axis_km":179517444.83999997,"periapsis_km":null,"mass_kg":3.4164980721274144e+27,"mass_msun":0.00171821,"constellation":"Aries","discovered":"2010","featured":false,"url":"https://spacecatalog.org/object/alf-ari-b","radius_km":85466.54000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"α Ari","host_v_mag":2.00538,"eccentricity":0.25,"uncertainties":{"mass_kg":[3.796089061804235e+26,3.796089061804235e+26],"distance_ly":[1.3188687598818638,1.3188687598818638],"eccentricity":[0.03,0.03],"host_mass_solar":[0.2,0.2],"host_radius_solar":[0.3,0.3],"host_temperature_k":[15,15],"orbital_period_days":[0.3,0.3],"argument_of_periastron_deg":[6.84,6.84]},"host_mass_solar":1.5,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":13.9,"planets_in_system":1,"discovery_facility":"Bohyunsan Optical Astronomical Observatory","host_spectral_type":"K2III","host_temperature_k":4553,"orbital_period_days":380.8,"periastron_epoch_bjd":2451213.52,"equilibrium_temperature_k":747.22,"argument_of_periastron_deg":89.16},"designations":[{"catalog":"Exoplanet","designation":"alf Ari b"},{"catalog":"Host star","designation":"alf Ari"}],"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."}