{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.831","julian_year":2026.831,"time":"2026-10-31T14:28:06.442Z","years_from_j2000":26.831,"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-103928","name":"HD 103928","class":"a9v_white_main_sequence_star","category":"star","object_type":"A9V white main-sequence star","mag":6.42,"mag_band":"V","abs_mag":3.058,"abs_mag_band":"V","distance_ly":153.41319691749146,"distance_method":"parallax","ra_deg":179.529945,"dec_deg":32.273907,"epoch_ra_deg":179.876658,"epoch_dec_deg":32.123186,"epoch_moved_arcsec":3.356,"pm_ra_mas_yr":-108.43,"pm_dec_mas_yr":-62.38,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ursa Major","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-103928","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":"11581+3216","age_years":894149000,"companions":[{"measured":2016,"magnitude":12.5,"components":"AB","discoverer_code":"BU  918","separation_arcsec":6.9,"position_angle_deg":236},{"measured":2015,"magnitude":11.5,"components":"AC","discoverer_code":"BU  918","separation_arcsec":133.3,"position_angle_deg":65},{"measured":2015,"magnitude":12.2,"components":"AD","discoverer_code":"WAL  59","separation_arcsec":141.5,"position_angle_deg":55}],"mass_solar":1.451,"radius_solar":1.508,"spectral_type":"A9V","color_index_bv":0.331,"luminosity_solar":5.209547473285552,"radial_velocity_km_s":2,"spectral_type_source":"SIMBAD (2007A&A...463..671R, quality D)","surface_gravity_log_g":4.073,"surface_temperature_k":7048,"proper_motion_ra_mas_yr":-108.43,"proper_motion_dec_mas_yr":-62.38,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":5.01},"designations":[{"catalog":"HD","designation":"HD 103928"},{"catalog":"HIP","designation":"HIP 58369"},{"catalog":"HR","designation":"HR 4574"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. HD 103928 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-103928","bibtex":"@misc{spacecatalog_hd-103928,\n  author       = {{SpaceCatalog}},\n  title        = {{HD 103928}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-103928},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-103928","release":"DR1","doi":null},"references":[{"bibcode":"2007A&A...463..671R","ads_url":"https://ui.adsabs.harvard.edu/abs/2007A%26A...463..671R/abstract","quantity":"properties.spectral_type_source"}],"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."}