{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T11:42:28.255Z","years_from_j2000":26.669,"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-147553","name":"HD 147553","class":"b9_5v_n_a1v_n_blue_white_main_sequence_star","category":"star","object_type":"B9.5V(n)+A1V(n) blue-white main-sequence star","mag":6.45,"mag_band":"V","abs_mag":1.24,"abs_mag_band":"V","distance_ly":359.20319421975927,"distance_method":"parallax","ra_deg":245.986335,"dec_deg":-33.199396,"epoch_ra_deg":246.419243,"epoch_dec_deg":-33.262022,"epoch_moved_arcsec":0.786,"pm_ra_mas_yr":-10.65,"pm_dec_mas_yr":-27.49,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Scorpius","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-147553","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"16239-3312","companions":[{"measured":2016,"magnitude":7.29,"components":"AB","discoverer_code":"HJ 4848","separation_arcsec":6.2,"position_angle_deg":153},{"measured":2016,"magnitude":9.48,"components":"AC","discoverer_code":"HJ 4848","separation_arcsec":94,"position_angle_deg":357}],"mass_solar":2.504,"radius_solar":1.835,"spectral_type":"B9.5V(n)+A1V(n)","color_index_bv":0.013,"luminosity_solar":27.797132677592884,"radial_velocity_km_s":-2,"spectral_type_source":"SIMBAD (1984ApJS...55..657C, quality C)","surface_gravity_log_g":4.286,"surface_temperature_k":10838,"proper_motion_ra_mas_yr":-10.65,"proper_motion_dec_mas_yr":-27.49,"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":41.069},"designations":[{"catalog":"HD","designation":"HD 147553"},{"catalog":"HIP","designation":"HIP 80324"},{"catalog":"HR","designation":"HR 6097"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","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."}