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Article
Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sagittarius B2(M)
Astronomy & Astrophysics (2010)
  • Neal A. Erickson, University of Massachusetts - Amherst
Abstract

H2O+ has been observed in its ortho- and para- states toward the massive star forming core Sgr B2(M), located close to the Galactic center. The observations show absorption in all spiral arm clouds between the Sun and Sgr B2. The average o/p ratio of H2O+ in most velocity intervals is 4.8, which corresponds to a nuclear spin temperature of 21 K. The relationship of this spin temperature to the formation temperature and current physical temperature of the gas hosting H2O+ is discussed, but no firm conclusion is reached. In the velocity interval 0 to 60 km/s, an ortho/para ratio of below unity is found, but if this is due to an artifact of contamination by other species or real is not clear.

Keywords
  • astrochemistry,
  • line: profiles,
  • molecular processes
Publication Date
October 1, 2010
Publisher Statement
This is the pre-published version harvested from arXiv. The published version is located at http://www.aanda.org/index.php?option=com_article&access=standard&Itemid=129&url=/articles/aa/abs/2010/13/aa15087-10/aa15087-10.html
Citation Information
Neal A. Erickson. "Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sagittarius B2(M)" Astronomy & Astrophysics Vol. 521 Iss. L11 (2010)
Available at: http://works.bepress.com/neal_erickson/7/