{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.675","julian_year":2026.675,"time":"2026-09-04T13:06:48.384Z","years_from_j2000":26.675,"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-300-c","name":"Kepler-300 c","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":3582.6647310295684,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":295.2886934,"dec_deg":48.5997243,"epoch_ra_deg":295.478298,"epoch_dec_deg":48.661748,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-300","semi_major_axis_km":34706706.002399996,"periapsis_km":null,"mass_kg":3.398163516773295e+25,"mass_msun":0.0000170899,"constellation":"Cygnus","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-300-c","radius_km":14350.725,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-300","host_v_mag":14.25,"eccentricity":0,"uncertainties":{"radius_km":[6633.224,6633.224],"distance_ly":[62.49156197052804,64.7094253390019],"host_mass_solar":[0.069,0.086],"host_radius_solar":[0.41,0.41],"host_temperature_k":[200,200],"orbital_period_days":[0.000245,0.000245]},"host_mass_solar":1.07,"inclination_deg":88.74,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.9,"planets_in_system":2,"discovery_facility":"Kepler","host_temperature_k":5986,"orbital_period_days":40.714955,"transit_midpoint_bjd":2454979.56443,"equilibrium_temperature_k":516},"designations":[{"catalog":"Exoplanet","designation":"Kepler-300 c"},{"catalog":"Host star","designation":"Kepler-300"}],"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."}