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Title: The enigma of the open cluster M29 (NGC 6913) solved

Determining the distance to the open cluster M29 (NGC 6913) has proven difficult, with distances determined by various authors differing by a factor of two or more. To solve this problem, we have initiated a new photometric investigation of the cluster in the Vilnius seven-color photometric system, supplementing it with available data in the BV and JHK {sub s} photometric systems and spectra of the nine brightest stars of spectral classes O and B. Photometric spectral classes and luminosities of 260 stars in a 15' × 15' area down to V = 19 mag are used to investigate the interstellar extinction run with distance and to estimate the distance of the Great Cygnus Rift, ∼ 800 pc. The interstellar reddening law in the optical and near-infrared regions is found to be close to normal, with the ratio of extinction to color excess R{sub BV} = 2.87. The extinction A{sub V} of cluster members is between 2.5 and 3.8 mag, with a mean value of 2.97 mag, or E {sub B–V} = 1.03. The average distance of eight stars of spectral types O9-B2 is 1.54 ± 0.15 kpc. Two stars from the seven brightest stars are field stars: HDE 229238 ismore » a background B0.5 supergiant and HD 194378 is a foreground F star. In the intrinsic color-magnitude diagram, seven fainter stars of spectral classes B3-B8 are identified as possible members of the cluster. The 15 selected members of the cluster of spectral classes O9-B8 plotted on the log L/L {sub ☉} versus log T {sub eff} diagram, together with the isochrones from the Padova database, give the age of the cluster as 5 ± 1 Myr.« less
Authors:
; ; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Institute of Theoretical Physics and Astronomy, Vilnius University, Goštauto 12, Vilnius LT-01108 (Lithuania)
  2. Vatican Observatory Research Group, Steward Observatory, Tucson, AZ 85721 (United States)
  3. U.S. Naval Observatory Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002 (United States)
  4. INAF Astronomical Observatory of Padova, I-36012, Asiago (VI) (Italy)
  5. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  6. University School "Ignatianum," Cracow (Poland)
Publication Date:
OSTI Identifier:
22342225
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 5; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COLOR; DISTANCE; LUMINOSITY; NEAR INFRARED RADIATION; SPECTRA; STAR CLUSTERS; STARS