Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C

61Citations
Citations of this article
22Readers
Mendeley users who have this article in their library.

Abstract

We present Herschel/HIFI observations of the fundamental rotational transitions of ortho-and para-H216O and H218O in absorption towards Sagittarius B2(M) and W31C. The ortho/para ratio in water in the foreground clouds on the line of sight towards these bright continuum sources is generally consistent with the statistical high-temperature ratio of 3, within the observational uncertainties. However, somewhat unexpectedly, we derive a low ortho/para ratio of 2.35 ± 0.35, corresponding to a spin temperature of ∼27 K, towards Sagittarius B2(M) at velocities of the expanding molecular ring. Water molecules in this region appear to have formed with, or relaxed to, an ortho/para ratio close to the value corresponding to the local temperature of the gas and dust. © 2010 ESO.

Cite

CITATION STYLE

APA

Lis, D. C., Phillips, T. G., Goldsmith, P. F., Neufeld, D. A., Herbst, E., Comito, C., … Zaal, P. (2010). Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C. Astronomy and Astrophysics, 521(1). https://doi.org/10.1051/0004-6361/201015072

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free