III/264 Spectral types of stars in Coalsack region (Vanas 1939) ================================================================================ A spectrophotometric study of stars in Cygnus Vanas E. =1939UppAn...1a...1V ================================================================================ ADC_Keywords: Spectral types Description (from B Skiff): This table shows coordinates and identifications for 1930 stars in northern Cygnus ('Northern Coalsack' region) classified by Erik Vanas in an early spectral survey. In the source paper, the stars were identified by BD number (part I of the catalogue) and by approximate coordinates for fainter non-BD stars (part II of the catalogue). The spectral types were determined from scans of objective-prism plates (~260{AA}/mm). Accurate coordinates of the BD stars were derived mainly from the Tycho-2 catalogue. The non-BD stars had to be identified one-by-one from DSS images via SkyView, usually unambiguous, and coordinates found in VizieR. For the non-BD stars, the acronym [V39] was used. For pairs or crowded stars, 2MASS positions are sometimes used. Where the type applies to a near-equal double star, the coordinates are for the mid-point between the two stars (rounded to 1" precision), and the magnitude is for the combined light. The original Vanas photo-blue magnitudes are somewhat uncertain, probably including a color term. Instead standard V magnitudes from Tycho-2 or from the TASS MkIV survey (Cat. II/271) are supplied. The Vanas spectral types are formally on the 'Uppsala' system, which includes the strength of the CN band to distinguish dwarfs and giants among types later than G5. These are shown in modern MK notation. The scheme also includes a pseudo-luminosity class for hot stars based largely on the width of the Balmer lines. Since the He lines were not involved in the classification, the system loses resolution (or 'granularity') for types earlier than A0. There is also the danger at this dispersion of mistaking a late-B supergiant for an early-B dwarf. From consideration of his descriptions of the spectra, and also comparison with types from modern sources for the same stars, these 'Greek-lettered' types were transformed in modern notation as: * types 'A0{mu}' given as A0V * types 'A0{sigma}' and 'A0{sigma}+' given as B8 * types 'B{tau}-' given as B, and are mainly B3 to B7 * types 'B{tau}' given as OB The classifications otherwise nominally match the HD scale. Further comparison with MK types suggests they are indeed very good, on a par with similar post-War surveys, and rather more accurate than HD types for the same stars. Vanas recognized several new metallic-line stars in this survey. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file catalog.dat 98 1930 Catalog of studied stars -------------------------------------------------------------------------------- See also: III/135 : Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989) Byte-by-byte Description of file: catalog.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Cat Catalog Name of the star, BD or [V39] (1) 7- 10 I4 --- No Star number, either BD or [V39] (1) 15- 16 I2 h RAh Right Ascension J2000 (hours) 18- 19 I2 min RAm Right Ascension J2000 (minutes) 21- 25 F5.2 s RAs Right Ascension J2000 (seconds) 27 A1 --- DE- Declination J2000 (sign) 28- 29 I2 deg DEd Declination J2000 (degrees) 31- 32 I2 arcmin DEm Declination J2000 (minutes) 34- 37 F4.1 arcsec DEs ? Declination J2000 (seconds) 39 A1 --- s [MTU*] Source of position (2) 41- 44 F4.1 mag Vmag Approximative V magnitude 47- 52 A6 --- SpT Spectral type, transformed from Uppsala (3) 58- 98 A41 --- Comm Remarks and comments, from B. Skiff -------------------------------------------------------------------------------- Note (1): "Cat" is BD for the first part (except "3586" at line 546 which represents the GSC field number for star originally named "+51 2938") and "[V39]" for the second part (non-BD stars) Note (2): Source is as follows: M = 2MASS (Cat. II/246) T = Tycho-2 (Cat. I/259) U = UCAC3 (Cat. I/315) * = star not found; the position is then the original position precessed to J2000, and the magnitude the original photographic magnitude. Note (3): the spectral types are formally on the 'Uppsala' system, which includes using the strength of the CN band to distinguish dwarfs and giants among types later than G5. These were converted into MK equivalents, see details in the "Description" section above. -------------------------------------------------------------------------------- History: Prepared essentially by B. Skiff (Lowell Obs.) ================================================================================ (End) Brian Skiff [Lowell Obs.], Francois Ochsenbein [CDS] 28-Dec-2010