{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.841","julian_year":2026.841,"time":"2026-11-04T01:52:11.999Z","years_from_j2000":26.841,"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-201433","name":"V389 Cyg","class":"b8v_blue_white_main_sequence_star","category":"star","object_type":"B8V blue-white main-sequence star","mag":5.6,"mag_band":"V","abs_mag":0.283,"abs_mag_band":"V","distance_ly":377.4956746640029,"distance_method":"parallax","ra_deg":317.16202499999997,"dec_deg":30.205637,"epoch_ra_deg":317.447841,"epoch_dec_deg":30.314525,"epoch_moved_arcsec":0.88,"pm_ra_mas_yr":25.35,"pm_dec_mas_yr":-20.78,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cygnus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-201433","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":"21086+3012","companions":[{"measured":2023,"magnitude":8.1,"components":"AB","discoverer_code":"STF2762","separation_arcsec":3.3,"position_angle_deg":303},{"measured":2021,"magnitude":10.22,"components":"AC","discoverer_code":"STF2762","separation_arcsec":59,"position_angle_deg":229},{"measured":2002,"magnitude":11.4,"components":"AD","discoverer_code":"STF2762","separation_arcsec":73.1,"position_angle_deg":66}],"mass_solar":3.087,"radius_solar":2.63,"spectral_type":"B8V","uncertainties":{"distance_ly":[22.5922409301839,25.664115469516723]},"color_index_bv":-0.048,"luminosity_solar":67.11197196984207,"variable_mag_max":5.557,"variable_mag_min":5.637,"radial_velocity_km_s":-26,"spectral_type_source":"SIMBAD (1977A&AS...30...71C, quality C)","variable_designation":"V389 Cyg","surface_gravity_log_g":4.001,"surface_temperature_k":11786,"proper_motion_ra_mas_yr":25.35,"proper_motion_dec_mas_yr":-20.78,"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":113.4479},"designations":[{"catalog":"HD","designation":"HD 201433"},{"catalog":"HIP","designation":"HIP 104371"},{"catalog":"HR","designation":"HR 8094"},{"catalog":"Variable star","designation":"V389 Cyg"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. V389 Cyg [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-201433","bibtex":"@misc{spacecatalog_hd-201433,\n  author       = {{SpaceCatalog}},\n  title        = {{V389 Cyg}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-201433},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-201433","release":"DR1","doi":null},"references":[{"bibcode":"1977A&AS...30...71C","ads_url":"https://ui.adsabs.harvard.edu/abs/1977A%26AS...30...71C/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."}