{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.674","julian_year":2026.674,"time":"2026-09-04T03:10:15.819Z","years_from_j2000":26.674,"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-58556","name":"HD 58556","class":"g1v_yellow_main_sequence_star","category":"star","object_type":"G1V yellow main-sequence star","mag":6.99,"mag_band":"V","abs_mag":4.234,"abs_mag_band":"V","distance_ly":116.02850059084288,"distance_method":"parallax","ra_deg":111.4884,"dec_deg":-2.248469,"epoch_ra_deg":111.826808,"epoch_dec_deg":-2.301868,"epoch_moved_arcsec":1.341,"pm_ra_mas_yr":-15.83,"pm_dec_mas_yr":-47.73,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Monoceros","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-58556","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"07260-0215","age_years":4890813400,"companions":[{"measured":2016,"magnitude":13.3,"components":null,"discoverer_code":"TOK 117","separation_arcsec":6.6,"position_angle_deg":140}],"mass_solar":1.064,"radius_solar":1.155,"spectral_type":"G1V","color_index_bv":0.568,"luminosity_solar":1.7635996338979947,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1999MSS...C05....0H, quality C)","surface_gravity_log_g":4.323,"surface_temperature_k":5983,"proper_motion_ra_mas_yr":-15.83,"proper_motion_dec_mas_yr":-47.73,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":1.531},"designations":[{"catalog":"HD","designation":"HD 58556"},{"catalog":"HIP","designation":"HIP 36071"}],"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."}