{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.681","julian_year":2026.681,"time":"2026-09-06T21:46:02.233Z","years_from_j2000":26.681,"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-155424","name":"HD 155424","class":"a3v_white_main_sequence_star","category":"star","object_type":"A3V white main-sequence star","mag":7.72,"mag_band":"V","abs_mag":1.279,"abs_mag_band":"V","distance_ly":633.3134941187311,"distance_method":"parallax","ra_deg":257.93061,"dec_deg":-4.640599,"epoch_ra_deg":258.286669,"epoch_dec_deg":-4.673635,"epoch_moved_arcsec":0.216,"pm_ra_mas_yr":-7.04,"pm_dec_mas_yr":4.01,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ophiuchus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-155424","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"17117-0438","age_years":297874120,"companions":[{"measured":2015,"magnitude":13.2,"components":null,"discoverer_code":"RST4567","separation_arcsec":4.5,"position_angle_deg":0}],"mass_solar":3.161,"radius_solar":4.471,"spectral_type":"A3V","color_index_bv":0.458,"luminosity_solar":26.816370667607295,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1999MSS...C05....0H, quality C)","surface_gravity_log_g":3.586,"surface_temperature_k":9862,"proper_motion_ra_mas_yr":-7.04,"proper_motion_dec_mas_yr":4.01,"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":169.6254},"designations":[{"catalog":"HD","designation":"HD 155424"},{"catalog":"HIP","designation":"HIP 84110"}],"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."}