{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T18:14:30.010Z","years_from_j2000":26.678,"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":"hat-p-38-b","name":"HAT-P-38 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":832.3706453157922,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":35.3834942,"dec_deg":32.2460441,"epoch_ra_deg":35.781508,"epoch_dec_deg":32.368994,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HAT-P-38","semi_major_axis_km":7823968.63761,"periapsis_km":null,"mass_kg":5.0678024875717306e+26,"mass_msun":0.000254867,"constellation":"Triangulum","discovered":"2012","featured":false,"url":"https://spacecatalog.org/object/hat-p-38-b","radius_km":58978.290700000005,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HAT-P-38","host_v_mag":12.525,"eccentricity":0.067,"uncertainties":{"mass_kg":[3.7959098967682008e+25,3.7959098967682008e+25],"radius_km":[4502.9386,6575.8211],"distance_ly":[7.915815287185363,8.065847220935064],"eccentricity":[0.047,0.047],"host_mass_solar":[0.044,0.044],"inclination_deg":[0.7,0.7],"host_radius_solar":[0.067,0.096],"host_temperature_k":[100,100],"semi_major_axis_km":[134638.08362999998,134638.08362999998],"orbital_period_days":[0.000032,0.000032],"argument_of_periastron_deg":[104,104]},"host_mass_solar":0.886,"inclination_deg":88.3,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.923,"planets_in_system":1,"discovery_facility":"HATNet","host_spectral_type":"G5","host_temperature_k":5330,"orbital_period_days":4.640382,"transit_midpoint_bjd":2455863.11957,"equilibrium_temperature_k":1082,"argument_of_periastron_deg":240},"designations":[{"catalog":"Exoplanet","designation":"HAT-P-38 b"},{"catalog":"Host star","designation":"HAT-P-38"}],"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."}