{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.667","julian_year":2026.667,"time":"2026-09-01T14:44:41.593Z","years_from_j2000":26.667,"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-57-b","name":"Kepler-57 b","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":2100.903691424631,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":293.6413146,"dec_deg":44.6570692,"epoch_ra_deg":293.84906,"epoch_dec_deg":44.715135,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-57","semi_major_axis_km":8957920.497515999,"periapsis_km":null,"mass_kg":1.4966252676685195e+26,"mass_msun":0.0000752674,"constellation":"Cygnus","discovered":"2012","featured":false,"url":"https://spacecatalog.org/object/kepler-57-b","radius_km":19995.3435,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-57","host_v_mag":15.017,"eccentricity":0.0162,"uncertainties":{"mass_kg":[2.9323344230855673e+25,3.0816386197803517e+25],"radius_km":[561.2728,574.029],"distance_ly":[28.142403051289207,28.142403051289207],"eccentricity":[0.0021,0.0024],"host_mass_solar":[0.049,0.049],"host_radius_solar":[0.019,0.019],"host_temperature_k":[90.8,90.8],"semi_major_axis_km":[88262.743713,88262.743713]},"host_mass_solar":0.859,"inclination_deg":88.9,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.826,"planets_in_system":2,"discovery_facility":"Kepler","host_temperature_k":5187.9,"orbital_period_days":5.72,"transit_midpoint_bjd":2454971.559971,"equilibrium_temperature_k":850},"designations":[{"catalog":"Exoplanet","designation":"Kepler-57 b"}],"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":"2026-08-30T09:56:50.739Z","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."}