{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-03T05:42:28.023Z","years_from_j2000":26.671,"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":"yildun","name":"Yildun","class":"a1van_white_main_sequence_star","category":"star","object_type":"A1Van white main-sequence star","mag":4.35,"mag_band":"V","abs_mag":0.738,"abs_mag_band":"V","distance_ly":172.11402514663638,"distance_method":"parallax","ra_deg":263.05377,"dec_deg":86.58646,"epoch_ra_deg":260.930691,"epoch_dec_deg":86.563756,"epoch_moved_arcsec":1.467,"pm_ra_mas_yr":10.54,"pm_dec_mas_yr":53.97,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ursa Minor","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/yildun","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"17322+8635","age_years":538299500,"companions":[{"measured":2009,"magnitude":11.8,"components":null,"discoverer_code":"DRS  59","separation_arcsec":4.5,"position_angle_deg":67}],"mass_solar":2.397,"radius_solar":3.071,"spectral_type":"A1Van","color_index_bv":0.021,"luminosity_solar":44.136714346343965,"radial_velocity_km_s":-8,"spectral_type_source":"SIMBAD (1987ApJS...65..581G, quality C)","surface_gravity_log_g":3.737,"surface_temperature_k":8880,"proper_motion_ra_mas_yr":10.54,"proper_motion_dec_mas_yr":53.97,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: above 7,500 K GSP-Phot's temperature and extinction are degenerate","bolometric_luminosity_solar":50.2629},"designations":[{"catalog":"Bayer/Flamsteed","designation":"23 Delta UMi"},{"catalog":"Common name","designation":"Yildun"},{"catalog":"HD","designation":"HD 166205"},{"catalog":"HIP","designation":"HIP 85822"},{"catalog":"HR","designation":"HR 6789"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"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."}