{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T17:24:05.839Z","years_from_j2000":26.678,"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":"k2-266-d","name":"K2-266 d","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":252.96232036781817,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":157.9356855,"dec_deg":0.9372782,"epoch_ra_deg":158.280727,"epoch_dec_deg":0.799375,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-266","semi_major_axis_km":15483379.617449999,"periapsis_km":null,"mass_kg":5.315229402334327e+25,"mass_msun":0.0000267311,"constellation":"Sextans","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-266-d","radius_km":18687.833000000002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-266","host_v_mag":11.625,"eccentricity":0.047,"uncertainties":{"mass_kg":[2.269423789760724e+25,3.4041356846410864e+25],"radius_km":[765.3720000000001,892.9340000000001],"distance_ly":[1.1575289845167223,1.1679659886036582],"eccentricity":[0.032,0.043],"host_mass_solar":[0.033,0.033],"inclination_deg":[0.25,0.32],"host_radius_solar":[0.022,0.024],"host_temperature_k":[57,49],"semi_major_axis_km":[254316.38018999997,239356.59312],"orbital_period_days":[0.00035,0.00034],"argument_of_periastron_deg":[62,62]},"host_mass_solar":0.686,"inclination_deg":89.46,"stars_in_system":2,"discovery_method":"Transit","host_radius_solar":0.703,"planets_in_system":4,"discovery_facility":"K2","host_temperature_k":4285,"orbital_period_days":14.697,"periastron_epoch_bjd":2457944.8,"transit_midpoint_bjd":2457944.8393,"equilibrium_temperature_k":538.3,"argument_of_periastron_deg":87},"designations":[{"catalog":"Exoplanet","designation":"K2-266 d"}],"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."}