{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.815","julian_year":2026.815,"time":"2026-10-25T15:24:09.452Z","years_from_j2000":26.815,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued position is carried along the great circle the object's own published motion puts it on, at a constant velocity, from the epoch that position was measured at, 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. The motion runs from position_epoch_jyear where the upstream publishes one — a timed pulsar's position belongs to the year it was timed — and from J2000 where it does not. 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-31647","name":"4 ω Aur","class":"a1v_white_main_sequence_star","category":"star","object_type":"A1V white main-sequence star","mag":4.93,"mag_band":"V","abs_mag":1.339,"abs_mag_band":"V","distance_ly":170.49465873127272,"distance_method":"parallax","ra_deg":74.81418000000001,"dec_deg":37.890245,"epoch_ra_deg":75.272686,"epoch_dec_deg":37.930383,"epoch_moved_arcsec":2.901,"pm_ra_mas_yr":46.26,"pm_dec_mas_yr":-97.81,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Auriga","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-31647","source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0","attribution":"HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.","commercial_use":"allowed"},"radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"04593+3753","age_years":217814060,"companions":[{"measured":2022,"magnitude":8.21,"components":"AB","discoverer_code":"STF 616","separation_arcsec":4.7,"position_angle_deg":5},{"measured":2002,"magnitude":12.09,"components":"AC","discoverer_code":"STF 616","separation_arcsec":163.5,"position_angle_deg":238}],"mass_solar":2.162,"radius_solar":1.803,"spectral_type":"A1V","color_index_bv":0.037,"luminosity_solar":25.374646458649643,"metallicity_fe_h":-0.12,"radial_velocity_km_s":5,"spectral_type_source":"SIMBAD (quality C)","surface_gravity_log_g":4.112,"surface_temperature_k":9580,"metallicity_fe_h_source":"One spectroscopic determination, compiled from the literature (PASTEL, Soubiran+ 2016)","proper_motion_ra_mas_yr":46.26,"proper_motion_dec_mas_yr":-97.81,"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":24.4653},"designations":[{"catalog":"Bayer/Flamsteed","designation":"4 Omega Aur"},{"catalog":"HD","designation":"HD 31647"},{"catalog":"HIP","designation":"HIP 23179"},{"catalog":"HR","designation":"HR 1592"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. 4 ω Aur [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-31647","bibtex":"@misc{spacecatalog_hd-31647,\n  author       = {{SpaceCatalog}},\n  title        = {{4 ω Aur}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-31647},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-31647","release":"DR1","doi":null},"references":[],"attribution":"Data from SpaceCatalog.org. Each record names its upstream in `source`, with that producer's terms in `source.license`, the acknowledgement it asks for in `source.attribution`, and whether its terms allow commercial use in `source.commercial_use`; those terms govern the record, and citing SpaceCatalog does not discharge them."}