{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.674","julian_year":2026.674,"time":"2026-09-04T03:36:23.011Z","years_from_j2000":26.674,"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":"wasp-4-b","name":"WASP-4 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":871.5094106418014,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":353.5629149,"dec_deg":-42.0617794,"epoch_ra_deg":353.92371,"epoch_dec_deg":-41.913416,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"WASP-4","semi_major_axis_km":3382407.856527,"periapsis_km":null,"mass_kg":2.2777495197080646e+27,"mass_msun":0.00114551,"constellation":"Phoenix","discovered":"2007","featured":false,"url":"https://spacecatalog.org/object/wasp-4-b","radius_km":96442.70770637601,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"WASP-4","host_v_mag":12.483,"eccentricity":0.0053,"uncertainties":{"mass_kg":[5.694373799270162e+25,6.073998716832639e+25],"radius_km":[857.904007837,786.4120124990001],"distance_ly":[11.969939062204483,12.299357003698393],"eccentricity":[0.0038,0.0038],"host_mass_solar":[0.031,0.033],"inclination_deg":[0.53,0.85],"host_radius_solar":[0.007,0.007],"host_temperature_k":[34,34],"semi_major_axis_km":[40391.425089,53855.233452],"orbital_period_days":[8.4e-8,8.4e-8],"argument_of_periastron_deg":[28,28]},"host_mass_solar":0.899,"inclination_deg":88.05,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.912,"planets_in_system":1,"discovery_facility":"SuperWASP","host_spectral_type":"G8","host_temperature_k":5436,"orbital_period_days":1.338230994,"transit_midpoint_bjd":2455804.51567913,"equilibrium_temperature_k":1653,"argument_of_periastron_deg":247},"designations":[{"catalog":"Exoplanet","designation":"WASP-4 b"},{"catalog":"Host star","designation":"WASP-4"}],"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."}