{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.674","julian_year":2026.674,"time":"2026-09-04T03:23:37.945Z","years_from_j2000":26.674,"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":"k2-263-b","name":"K2-263 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":529.9421440779419,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":129.6821253,"dec_deg":15.6806039,"epoch_ra_deg":130.058726,"epoch_dec_deg":15.586523,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-263","semi_major_axis_km":38491532.13110999,"periapsis_km":null,"mass_kg":9.197138516398724e+25,"mass_msun":0.0000462537,"constellation":"Cancer","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-263-b","radius_km":16028.1653,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-263","host_v_mag":11.568,"eccentricity":0.08,"uncertainties":{"mass_kg":[1.4930419669478448e+25,1.433320288269931e+25],"radius_km":[605.9195000000001,701.591],"distance_ly":[4.425942045616208,4.500958012491059],"eccentricity":[0.057,0.089],"host_mass_solar":[0.03,0.03],"inclination_deg":[0.035,0.045],"host_radius_solar":[0.02,0.02],"host_temperature_k":[44,44],"semi_major_axis_km":[448793.61209999997,433833.82502999995],"orbital_period_days":[0.000068,0.000066]},"host_mass_solar":0.88,"inclination_deg":89.271,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.85,"planets_in_system":1,"discovery_facility":"K2","host_spectral_type":"G9 V","host_temperature_k":5368,"orbital_period_days":50.819172,"transit_midpoint_bjd":2459534.0662,"equilibrium_temperature_k":482},"designations":[{"catalog":"Exoplanet","designation":"K2-263 b"},{"catalog":"Host star","designation":"K2-263"}],"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."}