{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T20:10:37.253Z","years_from_j2000":26.67,"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":"nn-ser-d","name":"NN Ser d","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1682.3733044109515,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":238.2337015,"dec_deg":12.9120871,"epoch_ra_deg":238.548909,"epoch_dec_deg":12.831783,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"NN Ser","semi_major_axis_km":507136781.673,"periapsis_km":null,"mass_kg":4.3275642246947246e+27,"mass_msun":0.00217639,"constellation":"Serpens","discovered":"2010","featured":false,"url":"https://spacecatalog.org/object/nn-ser-d","radius_km":84828.73000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"NN Ser","host_v_mag":16.943,"eccentricity":0.24,"uncertainties":{"mass_kg":[7.212587133931648e+26,7.212587133931648e+26],"distance_ly":[82.95787467225368,91.86520534769795],"eccentricity":[0.03,0.03],"semi_major_axis_km":[14959787.07,14959787.07],"orbital_period_days":[51,51],"argument_of_periastron_deg":[0.6,0.6]},"host_mass_solar":0.535,"stars_in_system":2,"discovery_method":"Eclipse Timing Variations","planets_in_system":2,"discovery_facility":"Multiple Observatories","host_spectral_type":"WD","host_temperature_k":57000,"orbital_period_days":2880,"periastron_epoch_bjd":2454563,"argument_of_periastron_deg":86.68},"designations":[{"catalog":"Exoplanet","designation":"NN Ser d"}],"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."}