{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.679","julian_year":2026.679,"time":"2026-09-06T03:45:58.828Z","years_from_j2000":26.679,"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":"k2-388-b","name":"K2-388 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":947.4679694482538,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":352.7139342,"dec_deg":-11.0773564,"epoch_ra_deg":353.062164,"epoch_dec_deg":-10.92924,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-388","semi_major_axis_km":null,"periapsis_km":null,"mass_kg":8.6596434082975e+25,"mass_msun":0.0000435506,"constellation":"Aquarius","discovered":"2022","featured":false,"url":"https://spacecatalog.org/object/k2-388-b","radius_km":24874.59,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-388","host_v_mag":12.861,"uncertainties":{"radius_km":[637.8100000000001,1275.6200000000001],"distance_ly":[13.646382843668546,14.041032060705803],"host_mass_solar":[0.04,0.04],"host_radius_solar":[0.038,0.038],"host_temperature_k":[100,100],"orbital_period_days":[0.00013,0.00013]},"host_mass_solar":0.93,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.91,"planets_in_system":1,"discovery_facility":"K2","host_spectral_type":"G8","host_temperature_k":5310,"orbital_period_days":6.33932,"transit_midpoint_bjd":2457741.79456,"equilibrium_temperature_k":874},"designations":[{"catalog":"Exoplanet","designation":"K2-388 b"},{"catalog":"Host star","designation":"K2-388"}],"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."}