{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.847","julian_year":2026.847,"time":"2026-11-06T05:57:52.731Z","years_from_j2000":26.847,"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-209942","name":"HD 209942","class":"f6iv_v_yellow_white_subgiant","category":"star","object_type":"F6IV-V yellow-white subgiant","mag":6.92,"mag_band":"V","abs_mag":4.541,"abs_mag_band":"V","distance_ly":97.5347816615481,"distance_method":"parallax","ra_deg":329.5538451623794,"dec_deg":82.869485,"epoch_ra_deg":329.260035,"epoch_dec_deg":82.997261,"epoch_moved_arcsec":4.001,"pm_ra_mas_yr":-129.14,"pm_dec_mas_yr":-74.41,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cepheus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-209942","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":"21582+8252","companions":[{"measured":2022,"magnitude":10.6,"components":"Aa,Ab","discoverer_code":"PKO  34","separation_arcsec":0.3,"position_angle_deg":229},{"measured":2024,"magnitude":7.47,"components":"AB","discoverer_code":"STF2873","separation_arcsec":13.7,"position_angle_deg":65},{"measured":2015,"magnitude":13,"components":"AC","discoverer_code":"STF2873","separation_arcsec":136.1,"position_angle_deg":200}],"spectral_type":"F6IV-V","uncertainties":{"distance_ly":[6.860246008630266,7.983275604349121],"metallicity_fe_h":[0.03,0.03]},"color_index_bv":0.517,"luminosity_solar":1.3292295883156824,"metallicity_fe_h":-0.32,"variable_mag_max":6.856,"variable_mag_min":7.216,"radial_velocity_km_s":-22,"spectral_type_source":"SIMBAD (2000A&AS..141..491C, quality D)","surface_gravity_log_g":4.3,"surface_temperature_k":6022,"metallicity_fe_h_source":"Median of 2 spectroscopic determinations in 3 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-129.14,"proper_motion_dec_mas_yr":-74.41,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 209942"},{"catalog":"HIP","designation":"HIP 108456"},{"catalog":"HR","designation":"HR 8423"}],"updated_at":"2026-11-04T19:31:31.075Z","citation":{"plain":"SpaceCatalog. HD 209942 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-209942","bibtex":"@misc{spacecatalog_hd-209942,\n  author       = {{SpaceCatalog}},\n  title        = {{HD 209942}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-209942},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-209942","release":"DR1","doi":null},"references":[{"bibcode":"2000A&AS..141..491C","ads_url":"https://ui.adsabs.harvard.edu/abs/2000A%26AS..141..491C/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."}