{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.675","julian_year":2026.675,"time":"2026-09-04T09:42:01.370Z","years_from_j2000":26.675,"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-157499","name":"HD 157499","class":"a2v_white_main_sequence_star","category":"star","object_type":"A2V white main-sequence star","mag":8.06,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":261.011625,"dec_deg":-11.701932,"epoch_ra_deg":261.38623,"epoch_dec_deg":-11.727112,"epoch_moved_arcsec":0.235,"pm_ra_mas_yr":-6.86,"pm_dec_mas_yr":-5.54,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Serpens","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-157499","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"17240-1142","companions":[{"measured":2019,"magnitude":9.48,"components":"AB","discoverer_code":"BU  242","separation_arcsec":1.2,"position_angle_deg":79},{"measured":2017,"magnitude":11.12,"components":"AC","discoverer_code":"BU  242","separation_arcsec":9.1,"position_angle_deg":64},{"measured":2017,"magnitude":10.53,"components":"AD","discoverer_code":"BU  242","separation_arcsec":48.3,"position_angle_deg":61}],"mass_solar":3.98,"radius_solar":15.342,"spectral_type":"A2V","color_index_bv":0.233,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1999MSS...C05....0H, quality C)","surface_gravity_log_g":2.547,"surface_temperature_k":5904,"proper_motion_ra_mas_yr":-6.86,"proper_motion_dec_mas_yr":-5.54,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":289.8854},"designations":[{"catalog":"HD","designation":"HD 157499"},{"catalog":"HIP","designation":"HIP 85151"}],"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."}