{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.685","julian_year":2026.685,"time":"2026-09-08T00:23:32.788Z","years_from_j2000":26.685,"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-21-b","name":"WASP-21 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":842.8728806782713,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":347.4928024,"dec_deg":18.3961597,"epoch_ra_deg":347.825648,"epoch_dec_deg":18.541799,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"WASP-21","semi_major_axis_km":7779089.276399999,"periapsis_km":null,"mass_kg":5.6941634535456906e+26,"mass_msun":0.000286368,"constellation":"Pegasus","discovered":"2010","featured":false,"url":"https://spacecatalog.org/object/wasp-21-b","radius_km":76473.41900000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"WASP-21","host_v_mag":11.59,"eccentricity":0,"uncertainties":{"mass_kg":[2.087869886579866e+25,2.087869886579866e+25],"radius_km":[3571.7360000000003,3571.7360000000003],"distance_ly":[9.279148946041351,9.48136590022573],"host_mass_solar":[0.03,0.03],"inclination_deg":[0.7,0.84],"host_radius_solar":[0.04,0.04],"host_temperature_k":[100,100],"semi_major_axis_km":[65823.063108,61335.126986999996],"orbital_period_days":[0.000024,0.000019]},"host_mass_solar":1.01,"inclination_deg":88.75,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.06,"planets_in_system":1,"discovery_facility":"SuperWASP","host_spectral_type":"G3 V","host_temperature_k":5800,"orbital_period_days":4.322482,"transit_midpoint_bjd":2454743.0419,"equilibrium_temperature_k":1333},"designations":[{"catalog":"Exoplanet","designation":"WASP-21 b"},{"catalog":"Host star","designation":"WASP-21"}],"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."}