{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.682","julian_year":2026.682,"time":"2026-09-07T02:10:16.855Z","years_from_j2000":26.682,"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":"gj-393-b","name":"GJ 393 b","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":22.93365308351504,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":157.2288672,"dec_deg":0.8378485,"epoch_ra_deg":157.573904,"epoch_dec_deg":0.700644,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"GJ 393","semi_major_axis_km":8081276.975213999,"periapsis_km":null,"mass_kg":1.0212407053923257e+25,"mass_msun":0.00000513597,"constellation":"Sextans","discovered":"2021","featured":false,"url":"https://spacecatalog.org/object/gj-393-b","radius_km":7462.377,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"GJ 393","host_v_mag":9.65,"uncertainties":{"mass_kg":[1.433320288269931e+24,1.433320288269931e+24],"distance_ly":[0.008104985986261073,0.008104985986261073],"host_mass_solar":[0.017,0.017],"host_radius_solar":[0.013,0.013],"host_temperature_k":[51,51],"semi_major_axis_km":[107710.466904,107710.466904],"orbital_period_days":[0.00085,0.00082]},"host_mass_solar":0.426,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":0.426,"planets_in_system":1,"discovery_facility":"Multiple Observatories","host_spectral_type":"M2.0 V","host_temperature_k":3579,"orbital_period_days":7.02679,"periastron_epoch_bjd":2458002.72,"equilibrium_temperature_k":485},"designations":[{"catalog":"Exoplanet","designation":"GJ 393 b"},{"catalog":"Host star","designation":"GJ 393"}],"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."}