{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-03T01:11:41.184Z","years_from_j2000":26.671,"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-255-c","name":"Kepler-255 c","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":3432.8937223820394,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":296.0642702,"dec_deg":45.9767647,"epoch_ra_deg":296.268279,"epoch_dec_deg":46.040619,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-255","semi_major_axis_km":13763004.104399998,"periapsis_km":null,"mass_kg":5.506338774103652e+25,"mass_msun":0.0000276922,"constellation":"Cygnus","discovered":"2014","featured":false,"url":"https://spacecatalog.org/object/kepler-255-c","radius_km":19070.519000000004,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-255","host_v_mag":15.699,"eccentricity":0,"uncertainties":{"radius_km":[7526.158,7526.158],"distance_ly":[101.28786309993467,101.28786309993467],"host_mass_solar":[0.032,0.064],"host_radius_solar":[0.368,0.368],"host_temperature_k":[200,200],"orbital_period_days":[0.000035,0.000035]},"host_mass_solar":0.867,"inclination_deg":89.91,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.933,"planets_in_system":3,"discovery_facility":"Kepler","host_temperature_k":5573,"orbital_period_days":9.946047,"transit_midpoint_bjd":2455004.70016,"equilibrium_temperature_k":807},"designations":[{"catalog":"Exoplanet","designation":"Kepler-255 c"},{"catalog":"Host star","designation":"Kepler-255"}],"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."}