CO AND H{sup +}{sub 3} TOWARD MWC 1080, MWC 349, AND LkH{alpha} 101
- Department of Physics and Astronomy, University of Missouri-St. Louis, St. Louis, MO 63121 (United States)
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978 (United States)
- Center for Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States)
- Eureka Scientific Inc., 1537 Kalaniwai Place, Honolulu, HI 96821 (United States)
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
We present high-resolution, near-infrared NIRSPEC observations of the fundamental rovibrational CO and H{sup +} {sub 3} R(1,0), R(1,1) {sup u}, and Q(1,0) transitions toward three early-type young stars: MWC 1080, MWC 349, and LkH{alpha} 101. These observations were performed for the purpose of constraining the physical characteristics of the interstellar material along each line of sight. Toward MWC 1080, we detected strong CO absorption and determined a column density upper limit of 1.4 x 10{sup 14} cm{sup -2} for H{sup +} {sub 3}. We infer that there is very little diffuse material along the line of sight toward MWC 1080 and that the CO absorption is consistent with an origin in the dispersing natal cloud. We detected both cold CO and H{sup +} {sub 3} toward MWC 349, consistent with a diffuse cloud origin. Similarly, both CO and H{sup +} {sub 3} were detected toward LkH{alpha} 101. Using a recently revised value for the cosmic ray ionization rate, we conclude that the CO absorption is consistent with a dense cloud origin while the H{sup +} {sub 3} could originate in either the dense or diffuse interstellar medium. We also find no evidence for CO fractionation toward LkH{alpha} 101 as reported by Goto et al.
- OSTI ID:
- 21450938
- Journal Information:
- Astrophysical Journal, Vol. 715, Issue 2; Other Information: DOI: 10.1088/0004-637X/715/2/757; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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