{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T16:31:39.807Z","years_from_j2000":26.673,"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-25680","name":"39 Tau","class":"g5v_yellow_main_sequence_star","category":"star","object_type":"G5V yellow main-sequence star","mag":5.9,"mag_band":"V","abs_mag":4.756,"abs_mag_band":"V","distance_ly":55.24338878852885,"distance_method":"parallax","ra_deg":61.33437,"dec_deg":22.008905,"epoch_ra_deg":61.732581,"epoch_dec_deg":22.081212,"epoch_moved_arcsec":5.765,"pm_ra_mas_yr":172.61,"pm_dec_mas_yr":-130.08,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Taurus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-25680","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"04053+2201","age_years":6198174500,"companions":[{"measured":2003,"magnitude":null,"components":"Aa,Ab","discoverer_code":"CHR 158","separation_arcsec":0.4,"position_angle_deg":252},{"measured":2015,"magnitude":12.6,"components":"AC","discoverer_code":"STT 559","separation_arcsec":150.1,"position_angle_deg":15},{"measured":2015,"magnitude":8.09,"components":"AB","discoverer_code":"STT 559","separation_arcsec":176.6,"position_angle_deg":357}],"mass_solar":0.983,"radius_solar":1.027,"spectral_type":"G5V","uncertainties":{"metallicity_fe_h":[0.031,0.031]},"color_index_bv":0.62,"luminosity_solar":1.0904355455436587,"metallicity_fe_h":0.05,"radial_velocity_km_s":23.9,"spectral_type_source":"SIMBAD (2011ARep...55...31S, quality C)","surface_gravity_log_g":4.406,"surface_temperature_k":5751,"metallicity_fe_h_source":"Median of 11 spectroscopic determinations in 12 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":172.61,"proper_motion_dec_mas_yr":-130.08,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: Gaia's classifier calls the source a binary, which GSP-Phot fitted as one star","bolometric_luminosity_solar":1.0338},"designations":[{"catalog":"Bayer/Flamsteed","designation":"39 Tau"},{"catalog":"Gliese","designation":"Gl 160"},{"catalog":"HD","designation":"HD 25680"},{"catalog":"HIP","designation":"HIP 19076"},{"catalog":"HR","designation":"HR 1262"}],"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."}