HYG Stellar database / Base de données stellaire HYG

Note: in this dataset, the stars whose distances are 100,000 parsecs are associated with defective data. As it can't be modified at the source, users have to exclude it manually : but if you exclude these stars from all distance-related analyzes, everything works perfectly well. "The database is a subset of the data in three major catalogs: the Hipparcos Catalog,the Yale Bright Star Catalog (5th Edition), and the Gliese Catalog of Nearby Stars (3rd Edition). Each of these catalogs contains information useful to amateur astronomers: * The Hipparcos catalog is the largest collection of high-accuracy stellar positional data, particularly parallaxes, which makes it useful as a starting point for stellar distance data. * The Yale Bright Star Catalog contains basic data on essentially all naked-eye stars, including much information (such as the traditional Bayer Greek letters and Flamsteed numbers) missing from many other catalogs * The Gliese catalog is the most comprehensive catalog of nearby stars (those within 75 light years of the Sun). It contains many fainter stars not found in Hipparcos. The name of the database comes from the three catalogs comprising its data: Hipparcos, Yale, and Gliese. This database contains ALL stars that are either brighter than a certain magnitude cutoff (magnitude +7.5 to +9.0) or within 50 parsecs (about 160 light years) from the Sun. The current version, v. 3.0, has no magnitude cutoff: any star in Hipparcos, Yale, or Gliese is represented." Source: [http://www.astronexus.com/hyg] and [https://github.com/astronexus/HYG-Database] Fields in the database: 1. id: The database primary key. 2. hip: The star's ID in the Hipparcos catalog, if known. 3. hd: The star's ID in the Henry Draper catalog, if known. 4. hr: The star's ID in the Harvard Revised catalog, which is the same as its number in the Yale Bright Star Catalog. 5. gl: The star's ID in the third edition of the Gliese Catalog of Nearby Stars. 6. bf: The Bayer / Flamsteed designation, primarily from the Fifth Edition of the Yale Bright Star Catalog. This is a combination of the two designations. The Flamsteed number, if present, is given first; then a three-letter abbreviation for the Bayer Greek letter; the Bayer superscript number, if present; and finally, the three-letter constellation abbreviation. Thus Alpha Andromedae has the field value "21Alp And", and Kappa1 Sculptoris (no Flamsteed number) has "Kap1Scl". 7. ra, dec: The star's right ascension and declination, for epoch and equinox 2000.0. 8. proper: A common name for the star, such as "Barnard's Star" or "Sirius". I have taken these names primarily from the Hipparcos project's web site, which lists representative names for the 150 brightest stars and many of the 150 closest stars. I have added a few names to this list. Most of the additions are designations from catalogs mostly now forgotten (e.g., Lalande, Groombridge, and Gould ["G."]) except for certain nearby stars which are still best known by these designations. 9. dist: The star's distance in parsecs, the most common unit in astrometry. To convert parsecs to light years, multiply by 3.262. A value >= 10000000 indicates missing or dubious (e.g., negative) parallax data in Hipparcos. 10. pmra, pmdec: The star's proper motion in right ascension and declination, in milliarcseconds per year. 11. rv: The star's radial velocity in km/sec, where known. 12. mag: The star's apparent visual magnitude. 13. absmag: The star's absolute visual magnitude (its apparent magnitude from a distance of 10 parsecs). 14. spect: The star's spectral type, if known. 15. ci: The star's color index (blue magnitude - visual magnitude), where known. 16. x,y,z: The Cartesian coordinates of the star, in a system based on the equatorial coordinates as seen from Earth. +X is in the direction of the vernal equinox (at epoch 2000), +Z towards the north celestial pole, and +Y in the direction of R.A. 6 hours, declination 0 degrees. 17. vx,vy,vz: The Cartesian velocity components of the star, in the same coordinate system described immediately above. They are determined from the proper motion and the radial velocity (when known). The velocity unit is parsecs per year; these are small values (around 1 millionth of a parsec per year), but they enormously simplify calculations using parsecs as base units for celestial mapping. 18. rarad, decrad, pmrarad, prdecrad: The positions in radians, and proper motions in radians per year. 19. bayer: The Bayer designation as a distinct value 20. flam: The Flamsteed number as a distinct value 21. con: The standard constellation abbreviation 22. comp, comp_primary, base: Identifies a star in a multiple star system. comp = ID of companion star, comp_primary = ID of primary star for this component, and base = catalog ID or name for this multi-star system. Currently only used for Gliese stars. 23. lum: Star's luminosity as a multiple of Solar luminosity. 24. var: Star's standard variable star designation, when known. 25. var_min, var_max: Star's approximate magnitude range, for variables. This value is based on the Hp magnitudes for the range in the original Hipparcos catalog, adjusted to the V magnitude scale to match the "mag" field."