{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T11:58:16.261Z","years_from_j2000":26.669,"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":"kepler-33-d","name":"Kepler-33 d","class":"neptune_like_planet","category":"exoplanet","object_type":"Neptune-like planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":3943.752456799775,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":289.0775348,"dec_deg":46.0051696,"epoch_ra_deg":289.274419,"epoch_dec_deg":46.05209,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-33","semi_major_axis_km":24863166.110339995,"periapsis_km":null,"mass_kg":2.3351176363064294e+25,"mass_msun":0.0000117436,"constellation":"Cygnus","discovered":"2011","featured":false,"url":"https://spacecatalog.org/object/kepler-33-d","radius_km":34122.835,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-33","host_v_mag":14.099,"eccentricity":0,"uncertainties":{"mass_kg":[1.0749902162024483e+25,1.116795391276988e+25],"radius_km":[3125.2690000000002,3125.2690000000002],"distance_ly":[72.3904080342312,72.3904080342312],"host_mass_solar":[0.121,0.063],"inclination_deg":[0.48,0.61],"host_radius_solar":[0.18,0.14],"host_temperature_k":[47,47],"semi_major_axis_km":[523592.54744999995,523592.54744999995],"orbital_period_days":[0.00011,0.00011]},"host_mass_solar":1.291,"inclination_deg":88.71,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.82,"planets_in_system":5,"discovery_facility":"Kepler","host_temperature_k":5904,"orbital_period_days":21.77596,"transit_midpoint_bjd":2455022.6342,"equilibrium_temperature_k":853},"designations":[{"catalog":"Exoplanet","designation":"Kepler-33 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":"2026-09-01T22:58:55.274Z","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."}