{"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":"2026-09-01T22:08:50.333Z","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":"hd-99573","name":"HD 99573","class":"b8_9v_blue_white_main_sequence_star","category":"star","object_type":"B8/9V blue-white main-sequence star","mag":8.84,"mag_band":"V","abs_mag":0.562,"abs_mag_band":"V","distance_ly":1475.820753497582,"distance_method":"parallax","ra_deg":171.711855,"dec_deg":-50.713818,"epoch_ra_deg":172.027012,"epoch_dec_deg":-50.86145,"epoch_moved_arcsec":0.286,"pm_ra_mas_yr":-10.7,"pm_dec_mas_yr":0.6,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Centaurus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-99573","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"11268-5043","companions":[{"measured":1937,"magnitude":10.3,"components":"AB","discoverer_code":"B  1189","separation_arcsec":0.3,"position_angle_deg":272},{"measured":2015,"magnitude":12.88,"components":"AB,C","discoverer_code":"HJ 4435","separation_arcsec":18.1,"position_angle_deg":191},{"measured":2015,"magnitude":9.29,"components":"AB,D","discoverer_code":"HJ 4435","separation_arcsec":28.1,"position_angle_deg":297}],"spectral_type":"B8/9V","color_index_bv":-0.006,"luminosity_solar":51.90390101970821,"variable_mag_max":8.785,"variable_mag_min":8.885,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1978MSS...C02....0H, quality D)","proper_motion_ra_mas_yr":-10.7,"proper_motion_dec_mas_yr":0.6},"designations":[{"catalog":"HD","designation":"HD 99573"},{"catalog":"HIP","designation":"HIP 55855"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"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."}