{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.672","julian_year":2026.672,"time":"2026-09-03T06:34:26.444Z","years_from_j2000":26.672,"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-20-d","name":"Kepler-20 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":921.5972455677617,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":287.6979913,"dec_deg":42.3385782,"epoch_ra_deg":287.911609,"epoch_dec_deg":42.382099,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-20","semi_major_axis_km":51970300.281179994,"periapsis_km":null,"mass_kg":8.002704942840449e+25,"mass_msun":0.0000402468,"constellation":"Lyra","discovered":"2011","featured":false,"url":"https://spacecatalog.org/object/kepler-20-d","radius_km":16621.3286,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-20","host_v_mag":12.61,"uncertainties":{"mass_kg":[2.1499804324048965e+25,2.2097021110828105e+25],"radius_km":[248.7459,338.0393],"distance_ly":[5.717521301374512,5.792537268249363],"host_mass_solar":[0.053,0.053],"inclination_deg":[0.053,0.17],"host_radius_solar":[0.0077,0.0087],"host_temperature_k":[50,50],"semi_major_axis_km":[1002305.7336899999,1002305.7336899999],"orbital_period_days":[0.000096,0.000096]},"host_mass_solar":0.929,"inclination_deg":89.708,"stars_in_system":2,"discovery_method":"Transit","host_radius_solar":0.9164,"planets_in_system":6,"discovery_facility":"Kepler","host_temperature_k":5495,"orbital_period_days":77.611455,"transit_midpoint_bjd":2454997.7296,"eccentricity_upper_limit":0.082,"equilibrium_temperature_k":430},"designations":[{"catalog":"Exoplanet","designation":"Kepler-20 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."}