{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.686","julian_year":2026.686,"time":"2026-09-08T16:13:47.195Z","years_from_j2000":26.686,"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":"wisep-j121756-91-162640-2-a-b","name":"WISEP J121756.91+162640.2 A b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":32.941794149391086,"distance_method":"NASA Exoplanet Archive sy_dist (Leggett+ 2014, 2014ApJ...780...62L)","ra_deg":184.487125,"dec_deg":16.4445,"epoch_ra_deg":184.828535,"epoch_dec_deg":16.295207,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"WISEP J121756.91+162640.2 A","semi_major_axis_km":1196782965.6,"periapsis_km":null,"mass_kg":4.175739773159732e+28,"mass_msun":0.0210004,"constellation":"Coma Berenices","discovered":"2012","featured":false,"url":"https://spacecatalog.org/object/wisep-j121756-91-162640-2-a-b","radius_km":66765.9508,"radius_kind":null,"data_quality":"The published mass and radius imply a density no material has. One of the two is likely an upper limit rather than a measurement.","description":null,"properties":{"host_star":"WISEP J121756.91+162640.2 A","uncertainties":{"mass_kg":[3.7982987639153173e+27,3.7982987639153173e+27],"radius_km":[2085.6387000000004,2085.6387000000004],"distance_ly":[4.5661892880344075,6.196971176618125],"host_mass_solar":[0.005,0.005],"host_radius_solar":[0.004,0.004],"host_temperature_k":[25,25],"semi_major_axis_km":[194477231.91,194477231.91]},"host_mass_solar":0.029,"stars_in_system":1,"discovery_method":"Imaging","host_radius_solar":0.091,"planets_in_system":1,"discovery_facility":"W. M. Keck Observatory","host_spectral_type":"T8.5","host_temperature_k":575,"equilibrium_temperature_k":450},"designations":[{"catalog":"Exoplanet","designation":"WISEP J121756.91+162640.2 A b"},{"catalog":"Host star","designation":"WISEP J121756.91+162640.2 A"}],"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."}