Contribution to the search for binaries among Am stars – VIII. New spectroscopic orbits of eight systems and statistical study of a sample of 91 Am stars |
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| Authors: | J-M Carquillat J-L Prieur |
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| Institution: | Jodrell Bank Observatory, University of Manchester, Macclesfield SK11 9DL;Solar–Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan;Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, the Netherlands |
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| Abstract: | Red clump giant (RCG) stars can be used as distance indicators to trace the mass distribution of the Galactic bar. We use RCG stars from 44 bulge fields from the OGLE-II microlensing collaboration data base to constrain analytic triaxial models for the Galactic bar. We find the bar major-axis is oriented at an angle of 24°–27° to the Sun–Galactic Centre line-of-sight. The ratio of semimajor and semiminor bar axis scalelengths in the Galactic plane x 0, y 0 , and vertical bar scalelength z 0, is x 0 : y 0 : z 0= 10 : 3.5 : 2.6 , suggesting a slightly more prolate bar structure than the working model of Gerhard which gives the scalelength ratios as x 0 : y 0 : z 0= 10 : 4 : 3 . |
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| Keywords: | Galaxy: bulge Galaxy: centre Galaxy: structure |
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