{"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":"2026-09-02T20:38:42.205Z","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":"kepler-104-d","name":"Kepler-104 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":1307.18583843205,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":287.6046621,"dec_deg":42.1665104,"epoch_ra_deg":287.81899,"epoch_dec_deg":42.209794,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-104","semi_major_axis_km":38446652.7699,"periapsis_km":null,"mass_kg":3.3087130254714773e+25,"mass_msun":0.00001664,"constellation":"Lyra","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-104-d","radius_km":22833.598,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-104","host_v_mag":12.697,"eccentricity":0,"uncertainties":{"mass_kg":[2.7640871250474388e+25,2.7640871250474388e+25],"radius_km":[3890.641,3890.641],"distance_ly":[14.305218726656367,14.621590413041606],"host_mass_solar":[0.008,0.013],"host_radius_solar":[0.223,0.223],"host_temperature_k":[74,74],"orbital_period_days":[0.00016,0.00016]},"host_mass_solar":0.818,"inclination_deg":89.14,"stars_in_system":2,"discovery_method":"Transit","host_radius_solar":1.349,"planets_in_system":3,"discovery_facility":"Kepler","host_temperature_k":5711,"orbital_period_days":51.755394,"transit_midpoint_bjd":2455104.08611,"equilibrium_temperature_k":515},"designations":[{"catalog":"Exoplanet","designation":"Kepler-104 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."}