{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.683","julian_year":2026.683,"time":"2026-09-07T14:45:48.653Z","years_from_j2000":26.683,"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-1577-b","name":"Kepler-1577 b","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":1663.4921117049294,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":292.9552704,"dec_deg":47.5730433,"epoch_ra_deg":293.147804,"epoch_dec_deg":47.629495,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-1577","semi_major_axis_km":9828580.104989998,"periapsis_km":null,"mass_kg":9.017973480364983e+24,"mass_msun":0.00000453527,"constellation":"Cygnus","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/kepler-1577-b","radius_km":7207.253,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-1577","host_v_mag":15.228,"eccentricity":0,"uncertainties":{"radius_km":[701.591,318.90500000000003],"distance_ly":[21.099056074496133,21.63721409772876],"host_mass_solar":[0.04,0.035],"host_radius_solar":[0.032,0.029],"host_temperature_k":[75.08,84.27],"orbital_period_days":[0.00003666,0.00003666]},"host_mass_solar":0.78,"inclination_deg":87.71,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.74,"planets_in_system":1,"discovery_facility":"Kepler","host_temperature_k":4862,"orbital_period_days":6.30560247,"transit_midpoint_bjd":2454964.53113,"equilibrium_temperature_k":1125},"designations":[{"catalog":"Exoplanet","designation":"Kepler-1577 b"},{"catalog":"Host star","designation":"Kepler-1577"}],"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."}