{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.687","julian_year":2026.687,"time":"2026-09-09T00:56:10.547Z","years_from_j2000":26.687,"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":"bd-20-2457-c","name":"BD+20 2457 c","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":5021.86236334247,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":154.186782,"dec_deg":19.8912626,"epoch_ra_deg":154.555175,"epoch_dec_deg":19.757382,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"BD+20 2457","semi_major_axis_km":300691720.10699993,"periapsis_km":null,"mass_kg":2.366871652859476e+28,"mass_msun":0.0119033,"constellation":"Leo","discovered":"2009","featured":false,"url":"https://spacecatalog.org/object/bd-20-2457-c","radius_km":79088.44,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"BD+20 2457","host_v_mag":9.743,"eccentricity":0.18,"uncertainties":{"distance_ly":[619.452500378525,619.452500378525],"eccentricity":[0.06,0.06],"host_mass_solar":[1.5,1.5],"host_radius_solar":[26,26],"host_temperature_k":[10,10],"orbital_period_days":[10.2,10.2],"argument_of_periastron_deg":[16.54,16.54]},"host_mass_solar":2.8,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":49,"planets_in_system":2,"discovery_facility":"McDonald Observatory","host_spectral_type":"K2 II","host_temperature_k":4137,"orbital_period_days":621.99,"periastron_epoch_bjd":2453866.95,"equilibrium_temperature_k":984.96,"argument_of_periastron_deg":126.02},"designations":[{"catalog":"Exoplanet","designation":"BD+20 2457 c"},{"catalog":"Host star","designation":"BD+20 2457"}],"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."}