FUENTE, Asuncion; GOICOECHEA, Javier; PETY, Jérôme; LE GAL, Romane; MARTÍN-DOMÉNECH, Rafael; GRATIER, P.; GUZMAN, Viviana; ROUEFF, Evelyne; LOISON, Jean Christophe; MUÑOZ-CARO, Guillermo M.; WAKELAM, Valentine; GERIN, Maryvonne; RIVIERE-MARICHALAR, Pablo; VIDAL, Thomas

doi:10.3847/2041-8213/aaa01b

Métadonnées

Licence d’utilisation du document

FUENTE, Asuncion
Observatorio Astronomico Nacional, Madrid

GOICOECHEA, Javier
Consejo Superior de Investigaciones Cientificas [España] = Spanish National Research Council [Spain] [CSIC]

PETY, Jérôme
Institut de RadioAstronomie Millimétrique [IRAM]
Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]

Langue

Article de revue

Ce document a été publié dans

The Astrophysical journal letters. 2017, vol. 851, n° 2, p. L49

Bristol : IOP Publishing

Résumé en anglais

We present the first detection of gas phase S2H in the Horsehead, a moderately UV-irradiated nebula. This confirms the presence of doubly sulfuretted species in the interstellar medium and opens a new challenge for sulfur chemistry. The observed S2H abundance is ~5x10$^{-11}$, only a factor 4-6 lower than that of the widespread H2S molecule. H2S and S2H are efficiently formed on the UV-irradiated icy grain mantles. We performed ice irradiation experiments to determine the H2S and S2H photodesorption yields. The obtained values are ~1.2x10$^{-3}$ and <1x10$^{-5}$ molecules per incident photon for H2S and S2H, respectively. Our upper limit to the S2H photodesorption yield suggests that photo-desorption is not a competitive mechanism to release the S2H molecules to the gas phase. Other desorption mechanisms such as chemical desorption, cosmic-ray desorption and grain shattering can increase the gaseous S2H abundance to some extent. Alternatively, S2H can be formed via gas phase reactions involving gaseous H2S and the abundant ions S+ and SH+. The detection of S2H in this nebula could be therefore the result of the coexistence of an active grain surface chemistry and gaseous photo-chemistry.< Réduire

Mots clés en anglais

Astrochemistry

methods: laboratory: solid state

ISM: abundances

ISM: molecules

photondominated region (PDR)

Horsehead

Métadonnées

Licence d’utilisation du document

First detection of interstellar S2H

Langue

Ce document a été publié dans

Résumé en anglais

Mots clés en anglais

DOI

Origine

Unités de recherche