{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.688","julian_year":2026.688,"time":"2026-09-09T05:15:27.504Z","years_from_j2000":26.688,"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":"kmt-2017-blg-0428l-b","name":"KMT-2017-BLG-0428L 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":17612.444396704144,"distance_method":"NASA Exoplanet Archive sy_dist (Zang+ 2023, 2023AJ....165..103Z)","ra_deg":271.38525,"dec_deg":-28.4902806,"epoch_ra_deg":271.810762,"epoch_dec_deg":-28.488431,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"KMT-2017-BLG-0428L","semi_major_axis_km":270772145.967,"periapsis_km":null,"mass_kg":3.338441838095381e+25,"mass_msun":0.0000167895,"constellation":"Sagittarius","discovered":"2023","featured":false,"url":"https://spacecatalog.org/object/kmt-2017-blg-0428l-b","radius_km":14223.163,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"KMT-2017-BLG-0428L","uncertainties":{"mass_kg":[1.6901235065849604e+25,2.1320639288015223e+25],"distance_ly":[8480.06582063533,5936.04607444473],"host_mass_solar":[0.17,0.22],"semi_major_axis_km":[88262743.71299998,82278828.885]},"host_mass_solar":0.34,"stars_in_system":1,"discovery_method":"Microlensing","planets_in_system":1,"discovery_facility":"KMTNet"},"designations":[{"catalog":"Exoplanet","designation":"KMT-2017-BLG-0428L b"},{"catalog":"Host star","designation":"KMT-2017-BLG-0428L"}],"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."}