{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.668","julian_year":2026.668,"time":"2026-09-02T01:12:14.443Z","years_from_j2000":26.668,"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":"k2-3-d","name":"K2-3 d","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":143.74592188196718,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":172.3353708,"dec_deg":-1.4551364,"epoch_ra_deg":172.678787,"epoch_dec_deg":-1.603026,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-3","semi_major_axis_km":30129011.158979997,"periapsis_km":null,"mass_kg":1.3138769309141034e+25,"mass_msun":0.00000660768,"constellation":"Leo","discovered":"2015","featured":false,"url":"https://spacecatalog.org/object/k2-3-d","radius_km":9299.2698,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-3","host_v_mag":12.168,"eccentricity":0.091,"uncertainties":{"radius_km":[325.2831,357.1736],"distance_ly":[0.352738122500658,0.352738122500658],"eccentricity":[0.064,0.12],"host_mass_solar":[0.027,0.029],"inclination_deg":[0.11,0.12],"host_radius_solar":[0.016,0.018],"host_temperature_k":[63,61],"semi_major_axis_km":[493672.97331,508632.76037999993],"orbital_period_days":[0.00012,0.00013],"argument_of_periastron_deg":[150,140]},"host_mass_solar":0.549,"inclination_deg":89.82,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.546,"planets_in_system":3,"discovery_facility":"K2","host_spectral_type":"M V","host_temperature_k":3844,"orbital_period_days":44.55603,"transit_midpoint_bjd":2457271.78796,"equilibrium_temperature_k":305.2,"argument_of_periastron_deg":0},"designations":[{"catalog":"Exoplanet","designation":"K2-3 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":"2026-09-01T22:58:55.274Z","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."}