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http://dx.doi.org/10.5140/JASS.2004.21.4.243

CO TO H2 RATIO OF INTERSTELLAR MOLECULAR CLOUDS IN THE DIRECTIONS OF EARLY TYPE STARS  

Park, Jae-Woo (Dept. of physics, Korea Advanced Institute of Science and Technology, Space Science Division, Korea Astronomy Observatory)
Lee, Dae-hee (Space Science Division, Korea Astronomy Observatory)
Min, Kyoung-Wook (Dept. of physics, Korea Advanced Institute of Science and Technology)
Publication Information
Journal of Astronomy and Space Sciences / v.21, no.4, 2004 , pp. 243-248 More about this Journal
Abstract
We present measurements of interstellar CO absorption lines in the spectra of 7 early-type stars that were observed with the FUSE(Far Ultraviolet Spectroscopic Explore.) Among 54 early-type target stars in the Galactic disk and halo observed with the BBFS(Berkeley Extreme and Far-ultraviolet Spectrometer), we choose 7 program stars (HD 37903, HD 97991, HD 149881, HD 156110, HD 164794, HD 214080 and HD 219188) which have only a single velocity component in the high-resolution optical measurements, in order to avoid line blending. To analyze the CO molecule, we select the E-X (0-0) band at $1076{\AA}$, which has a large oscillate. strength and is not blended with other interstellar absorption lines. We detect the CO absorption lines in three (HD 37903, HD 164794, and HD 214080) out of seven targets, and derive CO column densities for those targets. We also estimated the CO to $H_2$ ratios toward the three stars, based on the previously estimated $H_2$ column densities.
Keywords
ultraviolet astronomical observations; molecular clouds;
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