{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T22:01:56.441Z","years_from_j2000":26.673,"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":"k2-38-c","name":"K2-38 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":628.4707242223928,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":240.0333095,"dec_deg":-23.1894196,"epoch_ra_deg":240.432584,"epoch_dec_deg":-23.265632,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-38","semi_major_axis_km":14232741.418397998,"periapsis_km":null,"mass_kg":4.956899330266845e+25,"mass_msun":0.000024929,"constellation":"Scorpius","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/k2-38-c","radius_km":14605.849,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-38","host_v_mag":11.344,"eccentricity":0.161,"uncertainties":{"mass_kg":[7.763818228128793e+24,7.763818228128793e+24],"radius_km":[1658.306,1658.306],"distance_ly":[8.470281129303826,8.705113721259883],"eccentricity":[0.078,0.096],"host_mass_solar":[0.02,0.04],"inclination_deg":[0.28,0.31],"host_radius_solar":[0.06,0.09],"host_temperature_k":[66,66],"semi_major_axis_km":[140621.998458,136134.06233699998],"orbital_period_days":[0.0009,0.0009],"argument_of_periastron_deg":[33,54]},"host_mass_solar":1.03,"inclination_deg":87.68,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.06,"planets_in_system":2,"discovery_facility":"K2","host_spectral_type":"G2 V","host_temperature_k":5731,"orbital_period_days":10.56103,"transit_midpoint_bjd":2456900.4752,"equilibrium_temperature_k":916,"argument_of_periastron_deg":153},"designations":[{"catalog":"Exoplanet","designation":"K2-38 c"}],"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."}