{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.813","julian_year":2026.813,"time":"2026-10-24T19:42:03.950Z","years_from_j2000":26.813,"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-66791","name":"HD 66791","class":"g3v_yellow_main_sequence_star","category":"star","object_type":"G3V yellow main-sequence star","mag":8.72,"mag_band":"V","abs_mag":4.394,"abs_mag_band":"V","distance_ly":239.11763444649785,"distance_method":"parallax","ra_deg":120.97416000000001,"dec_deg":-31.544257,"epoch_ra_deg":121.239323,"epoch_dec_deg":-31.618826,"epoch_moved_arcsec":4.452,"pm_ra_mas_yr":-74.05,"pm_dec_mas_yr":148.61,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Puppis","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-66791","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":"08039-3133","age_years":8677648000,"companions":[{"measured":2023,"magnitude":9.71,"components":"AB","discoverer_code":"LDS 201","separation_arcsec":47.8,"position_angle_deg":237},{"measured":2023,"magnitude":10.93,"components":"AC","discoverer_code":"LDS 201","separation_arcsec":74,"position_angle_deg":255}],"mass_solar":1.054,"radius_solar":1.576,"spectral_type":"G3V","color_index_bv":0.689,"luminosity_solar":1.5219486509036517,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1982MSS...C03....0H, quality C)","surface_gravity_log_g":4.062,"surface_temperature_k":5771,"proper_motion_ra_mas_yr":-74.05,"proper_motion_dec_mas_yr":148.61,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":2.4733},"designations":[{"catalog":"HD","designation":"HD 66791"},{"catalog":"HIP","designation":"HIP 39457"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. HD 66791 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-66791","bibtex":"@misc{spacecatalog_hd-66791,\n  author       = {{SpaceCatalog}},\n  title        = {{HD 66791}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-66791},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-66791","release":"DR1","doi":null},"references":[{"bibcode":"1982MSS...C03....0H","ads_url":"https://ui.adsabs.harvard.edu/abs/1982MSS...C03....0H/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."}