New Constraints on the Sulfur Reservoir in the Dense Interstellar Medium Provided by Spitzer Observations of S I in Shocked Gas
Langue
en
Article de revue
Ce document a été publié dans
The Astrophysical Journal. 2013-12, vol. 779, p. 141
American Astronomical Society
Résumé en anglais
We present observations of fine-structure line emission of atomic sulfur, iron, and rotational lines of molecular hydrogen in shocks associated with several Class 0 protostars obtained with the Infrared Spectrograph of the ...Lire la suite >
We present observations of fine-structure line emission of atomic sulfur, iron, and rotational lines of molecular hydrogen in shocks associated with several Class 0 protostars obtained with the Infrared Spectrograph of the Spitzer Space Telescope. We use these observations to investigate the "missing sulfur problem," that significantly less sulfur is found in dense regions of the interstellar medium (ISM) than in diffuse regions. For sources where the sulfur fine-structure line emission is co-spatial with the detected molecular hydrogen emission and in the presence of weak iron emission, we derive sulfur and H2 column densities for the associated molecule-dominated C-shocks. We find the S I abundance to be gsim5%-10% of the cosmic sulfur abundance, indicating that atomic sulfur is a major reservoir of sulfur in shocked gas. This result suggests that in the quiescent dense ISM sulfur is present in some form that is released from grains as atoms, perhaps via sputtering, within the shock.< Réduire
Mots clés en anglais
astrochemistry
ISM: abundances
ISM: atoms
ISM: molecules
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