{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.846","julian_year":2026.846,"time":"2026-11-05T21:55:21.678Z","years_from_j2000":26.846,"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":"secunda-hyadum","name":"Secunda Hyadum","class":"g9_5iiicn0_5_yellow_giant","category":"star","object_type":"G9.5IIICN0.5 yellow giant","mag":3.77,"mag_band":"V","abs_mag":0.377,"abs_mag_band":"V","distance_ly":155.60888165228056,"distance_method":"parallax","ra_deg":65.73371777384838,"dec_deg":17.542514,"epoch_ra_deg":66.123774,"epoch_dec_deg":17.605565,"epoch_moved_arcsec":2.994,"pm_ra_mas_yr":107.75,"pm_dec_mas_yr":-28.84,"position_epoch_jyear":null,"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/secunda-hyadum","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":"04230+1732","companions":[{"measured":2004,"magnitude":9.5,"components":"Aa,Ab","discoverer_code":"CHR 262","separation_arcsec":0.5,"position_angle_deg":2},{"measured":2023,"magnitude":15.7,"components":"AC","discoverer_code":"SMR  85","separation_arcsec":25.6,"position_angle_deg":231},{"measured":2023,"magnitude":15.1,"components":"AD","discoverer_code":"SMR  85","separation_arcsec":78.9,"position_angle_deg":312},{"measured":2023,"magnitude":13.21,"components":"AB","discoverer_code":"BUP  55","separation_arcsec":112.6,"position_angle_deg":336}],"spectral_type":"G9.5IIICN0.5","uncertainties":{"distance_ly":[4.19002767520464,4.428517964862981],"metallicity_fe_h":[0.138,0.138]},"color_index_bv":0.983,"luminosity_solar":61.54602373713163,"metallicity_fe_h":0.09,"radial_velocity_km_s":39,"spectral_type_source":"SIMBAD (1989ApJS...71..245K, quality B)","surface_gravity_log_g":2.7,"surface_temperature_k":4975,"metallicity_fe_h_source":"Median of 23 spectroscopic determinations in 26 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":107.75,"proper_motion_dec_mas_yr":-28.84,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"61 Delta1 Tau"},{"catalog":"Common name","designation":"Secunda Hyadum"},{"catalog":"HD","designation":"HD 27697"},{"catalog":"HIP","designation":"HIP 20455"},{"catalog":"HR","designation":"HR 1373"}],"updated_at":"2026-11-04T19:31:31.075Z","citation":{"plain":"SpaceCatalog. Secunda Hyadum [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/secunda-hyadum","bibtex":"@misc{spacecatalog_secunda-hyadum,\n  author       = {{SpaceCatalog}},\n  title        = {{Secunda Hyadum}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/secunda-hyadum},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/secunda-hyadum","release":"DR1","doi":null},"references":[{"bibcode":"1989ApJS...71..245K","ads_url":"https://ui.adsabs.harvard.edu/abs/1989ApJS...71..245K/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."}