{"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":"2026-09-02T11:37:35.969Z","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-249-d","name":"Kepler-249 d","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":621.0050047364566,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":296.9853002,"dec_deg":43.6586043,"epoch_ra_deg":297.201179,"epoch_dec_deg":43.724628,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-249","semi_major_axis_km":14510993.457899999,"periapsis_km":null,"mass_kg":1.845399871147536e+25,"mass_msun":0.00000928078,"constellation":"Cygnus","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-249-d","radius_km":10013.617,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-249","host_v_mag":16.37,"eccentricity":0,"uncertainties":{"radius_km":[892.9340000000001,892.9340000000001],"distance_ly":[3.977477026255686,3.977477026255686],"host_mass_solar":[0.020399,0.020399],"host_radius_solar":[0.018,0.018],"host_temperature_k":[150,150],"orbital_period_days":[0.00007,0.00007]},"host_mass_solar":0.510238,"inclination_deg":89.86,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.482,"planets_in_system":3,"discovery_facility":"Kepler","host_spectral_type":"M2 V","host_temperature_k":3568,"orbital_period_days":15.368459,"transit_midpoint_bjd":2454980.38889,"equilibrium_temperature_k":332},"designations":[{"catalog":"Exoplanet","designation":"Kepler-249 d"},{"catalog":"Host star","designation":"Kepler-249"}],"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."}