{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T11:38:07.955Z","years_from_j2000":26.678,"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-1257-b","name":"Kepler-1257 b","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":3607.126459358324,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":296.0756231,"dec_deg":45.6270165,"epoch_ra_deg":296.281423,"epoch_dec_deg":45.690933,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-1257","semi_major_axis_km":5624879.93832,"periapsis_km":null,"mass_kg":1.7438730173950827e+25,"mass_msun":0.00000877019,"constellation":"Cygnus","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/kepler-1257-b","radius_km":9694.712000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-1257","host_v_mag":15.644,"eccentricity":0,"uncertainties":{"radius_km":[765.3720000000001,1148.058],"distance_ly":[139.88847040271125,139.88847040271125],"host_mass_solar":[0.053,0.056],"host_radius_solar":[0.067,0.096],"host_temperature_k":[93.92,168.32],"orbital_period_days":[0.000009861,0.000009861]},"host_mass_solar":0.9,"inclination_deg":87.65,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.87,"planets_in_system":1,"discovery_facility":"Kepler","host_temperature_k":5502,"orbital_period_days":2.668313762,"transit_midpoint_bjd":2454964.68877,"equilibrium_temperature_k":1252},"designations":[{"catalog":"Exoplanet","designation":"Kepler-1257 b"},{"catalog":"Host star","designation":"Kepler-1257"}],"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."}