{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T19:07:23.519Z","years_from_j2000":26.67,"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-644-b","name":"Kepler-644 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":4298.9041364955365,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":295.4757022,"dec_deg":43.4931119,"epoch_ra_deg":295.690728,"epoch_dec_deg":43.555583,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-644","semi_major_axis_km":6942837.179187,"periapsis_km":null,"mass_kg":6.031889546469293e+25,"mass_msun":0.0000303352,"constellation":"Cygnus","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/kepler-644-b","radius_km":20091.015,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-644","host_v_mag":14.031,"eccentricity":0,"uncertainties":{"radius_km":[3890.641,7398.596],"distance_ly":[120.62893629853755,120.62893629853755],"host_mass_solar":[0.165,0.221],"host_radius_solar":[0.349,0.668],"host_temperature_k":[238.58,156.03],"semi_major_axis_km":[43383.38250299999,43383.38250299999],"orbital_period_days":[0.000004229,0.000004229]},"host_mass_solar":1.49,"inclination_deg":78.65,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.81,"planets_in_system":1,"discovery_facility":"Kepler","host_temperature_k":6747,"orbital_period_days":3.173917103,"transit_midpoint_bjd":2455003.92435,"equilibrium_temperature_k":1655},"designations":[{"catalog":"Exoplanet","designation":"Kepler-644 b"},{"catalog":"Host star","designation":"Kepler-644"}],"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":"2026-09-02T18:38:07.546Z","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."}