2010A&A...518L.115C


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.24CET02:11:39

2010A&A...518L.115C - Astronomy and Astrophysics, volume 518, L115-115 (2010/7-2)

The 35Cl/37Cl isotopic ratio in dense molecular clouds: HIFI observations of hydrogen chloride towards W 3A.

CERNICHARO J., GOICOECHEA J.R., DANIEL F., AGUNDEZ M., CAUX E., DE GRAAUW T., DE JONGE A., KESTER D., LEDUC H.G., STEINMETZ E., STUTZKI J. and WARD J.S.

Abstract (from CDS):

We report on the detection with the HIFI instrument on board the Herschel satellite of the two hydrogen chloride isotopologues, H35Cl and H37Cl, towards the massive star-forming region W3A. The J=1-0 line of both species was observed with receiver 1b of the HIFI instrument at ∼625.9 and ∼624.9GHz. The different hyperfine components were resolved. The observations were modeled with a non-local, non-LTE radiative transfer model that includes hyperfine line overlap and radiative pumping by dust. Both effects are found to play an important role in the emerging intensity from the different hyperfine components. The inferred H35Cl column density (a few times ∼1014cm–2), and fractional abundance relative to H nuclei (∼7.5x10–10), supports an upper limit to the gas phase chlorine depletion of ≃200. Our best-fit model estimate of the H35Cl/H37Cl abundance ratio is ≃2.1±0.5, slightly lower, but still compatible with the solar isotopic abundance ratio (≃3.1). Since both species were observed simultaneously, this is the first accurate estimation of the [35Cl]/[37Cl] isotopic ratio in molecular clouds. Our models indicate that even for large line opacities and possible hyperfine intensity anomalies, the H35Cl and H37Cl J=1-0 integrated line-intensity ratio provides a good estimate of the 35Cl/37Cl isotopic abundance ratio.

Abstract Copyright:

Journal keyword(s): astrochemistry - ISM: clouds - ISM: molecules - ISM: individual objects: W3 - radiative transfer - radio lines: ISM

Simbad objects: 10

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Number of rows : 10

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 2MASS J02254334+6206154 Y*O 02 25 43.3308577441 +62 06 15.428915162     19.41 17.68 15.92 O8V-O9V 22 0
2 IC 1795 HII 02 25 43.5 +62 06 13           ~ 229 0
3 MPCM J022544.35+620611.7 HII 02 25 44.26 +62 06 16.2           O6.5V-O7.5V 35 0
4 W 3 MoC 02 27 04.10 +61 52 27.1           ~ 969 3
5 NAME Per Arm PoG 03 30 +45.0           ~ 1287 0
6 NAME OMC-1 MoC 05 35 14 -05 22.4           ~ 1030 2
7 NAME Orion Core ? 05 35 14.5 -05 22 30           ~ 176 0
8 NAME Mon R2 HII 06 07 47.58 -06 22 42.6           ~ 661 2
9 IRC +10216 C* 09 47 57.40632 +13 16 43.5648     10.96     C9,5e 2173 0
10 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1965 1

    Equat.    Gal    SGal    Ecl

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2021.01.24-02:11:39

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