{"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":"2026-09-05T19:13:26.339Z","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":"k2-189-b","name":"K2-189 b","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":789.666990781339,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":203.6214411,"dec_deg":-15.0365158,"epoch_ra_deg":203.981334,"epoch_dec_deg":-15.174263,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-189","semi_major_axis_km":5400483.13227,"periapsis_km":null,"mass_kg":1.5229028062868016e+25,"mass_msun":0.0000076589,"constellation":"Virgo","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-189-b","radius_km":8948.4743,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-189","host_v_mag":12.398,"uncertainties":{"radius_km":[274.2583,503.86990000000003],"distance_ly":[6.229586814389799,6.327433727704822],"host_mass_solar":[0.03,0.03],"inclination_deg":[2.82401,1.35119],"host_radius_solar":[0.034,0.034],"host_temperature_k":[100,100],"semi_major_axis_km":[59839.14828,59839.14828],"orbital_period_days":[0.00011,0.00011]},"host_mass_solar":0.85,"inclination_deg":88.11337,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.879,"planets_in_system":2,"discovery_facility":"K2","host_temperature_k":5442,"orbital_period_days":2.58812,"transit_midpoint_bjd":2457222.1466,"equilibrium_temperature_k":1203},"designations":[{"catalog":"Exoplanet","designation":"K2-189 b"}],"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."}