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Large atomic oxygen abundance towards the molecular cloud L1689N

Caux, E.; Ceccarelli, C.; Castets, A.; Vastel, C.; Liseau, R.; Molinari, S.; Nisini, B.; Saraceno, P. and White, G. J. (1999). Large atomic oxygen abundance towards the molecular cloud L1689N. Astronomy & Astrophysics, 347 L1-L4.

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We present spectroscopic ISO-LWS observations of the [OI] (63 μm and 145 μm), the [CII] (158 μm) and the H2O (179 μm) lines towards the molecular cloud L1689N. From the observed ratio of the two [OI] lines, we deduce a mean gas temperature of (26±0.5) K, an H2 density ≥ 3 x 104 cm-3 and an [OI] column density ≥ 5 x 1019 cm-2. Combining these observations with previous CO observations, we obtain [OI]/[CO] ~ 50. This ratio implies that up to 98% of oxygen abundance is in atomic form in the gas phase. Furthermore, assuming all the gaseous carbon is locked into the CO, carbon has to be depleted by more than a factor 24. Finally, the upper limit derived for the H2O (179 μm) line (3 x 10-13 erg s-1 cm-2 ) implies that the water abundance in this region is less than 6 x 10-7 with respect to H nuclei.

Item Type: Journal Article
Copyright Holders: 1999 European Southern Observatory
ISSN: 1432-0746
Keywords: stellar formation; jets and outflows; lines and bands
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 33303
Depositing User: G. J. White
Date Deposited: 26 Apr 2012 14:25
Last Modified: 24 Feb 2016 18:00
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