{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.677","julian_year":2026.677,"time":"2026-09-05T05:56:40.096Z","years_from_j2000":26.677,"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":"18-del-b","name":"18 Del b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":248.60291422325614,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":314.6078375,"dec_deg":10.8391378,"epoch_ra_deg":314.93124,"epoch_dec_deg":10.94282,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"18 Del","semi_major_axis_km":370404327.85319996,"periapsis_km":null,"mass_kg":1.7476033189966098e+28,"mass_msun":0.00878895,"constellation":"Delphinus","discovered":"2008","featured":false,"url":"https://spacecatalog.org/object/18-del-b","radius_km":79726.25,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"18 Del","host_v_mag":5.51048,"eccentricity":0.024,"uncertainties":{"mass_kg":[1.4615559418723966e+26,3.036999359610753e+26],"distance_ly":[2.027714200264994,2.027714200264994],"eccentricity":[0.018,0.007],"host_mass_solar":[0.09,0.13],"host_radius_solar":[0.4,0.61],"semi_major_axis_km":[299195.7414,299195.7414],"orbital_period_days":[0.92,1.06],"argument_of_periastron_deg":[57.98,28.8]},"host_mass_solar":2.1,"stars_in_system":2,"discovery_method":"Radial Velocity","host_radius_solar":8.8,"planets_in_system":1,"discovery_facility":"Okayama Astrophysical Observatory","host_spectral_type":"G6 III","host_temperature_k":4980,"orbital_period_days":982.85,"periastron_epoch_bjd":2454356.1,"equilibrium_temperature_k":452.72,"argument_of_periastron_deg":64.11},"designations":[{"catalog":"Exoplanet","designation":"18 Del b"},{"catalog":"Host star","designation":"18 Del"}],"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."}