{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.667","julian_year":2026.667,"time":"2026-09-01T11:04:37.878Z","years_from_j2000":26.667,"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":"k2-101-b","name":"K2-101 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":614.2503061539429,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":130.3439097,"dec_deg":18.9338205,"epoch_ra_deg":130.727268,"epoch_dec_deg":18.838443,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-101","semi_major_axis_km":16814800.666679997,"periapsis_km":null,"mass_kg":2.783030226390783e+25,"mass_msun":0.0000139963,"constellation":"Cancer","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/k2-101-b","radius_km":12756.2,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-101","host_v_mag":12.892,"eccentricity":0.1,"uncertainties":{"radius_km":[446.46700000000004,892.9340000000001],"distance_ly":[6.7905757840625975,6.9406077178123],"eccentricity":[0.08,0.18],"host_mass_solar":[0.03,0.02],"inclination_deg":[0.07,0.07],"host_radius_solar":[0.01,0.01],"host_temperature_k":[46,47],"semi_major_axis_km":[3575389.1097299997,1421179.7716499998],"orbital_period_days":[0.0000203,0.0000201],"argument_of_periastron_deg":[118,152]},"host_mass_solar":0.82,"inclination_deg":89.26,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.76,"planets_in_system":1,"discovery_facility":"K2","host_spectral_type":"K3","host_temperature_k":4927,"orbital_period_days":14.6762429,"transit_midpoint_bjd":2457152.6849877,"equilibrium_temperature_k":618,"argument_of_periastron_deg":0},"designations":[{"catalog":"Exoplanet","designation":"K2-101 b"},{"catalog":"Host star","designation":"K2-101"}],"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":"2026-08-30T09:56:50.739Z","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."}