The CHESS spectral survey of star forming regions: peering into the protostellar shock L1157-B1. I. Shock chemical complexity [Letter]

Codella, C., Lefloch, B., Ceccarelli, C., Cernicharo, J., Caux, E., Lorenzani, A., Viti, S., Hily-Blant, P., Parise, Berengere, Maret, S., Nisini, B., Caselli, P., Cabrit, S., Pagani, L., Benedettini, M., Boogert, A., Gueth, F., Melnick, G., Neufeld, D., Pacheco, S., Salez, M., Schuster, K., Bacmann, A., Baudry, A., Bell, T., Bergin, E. A., Blake, G., Bottinelli, S., Castets, A., Comito, C., Coutens, A., Crimier, N., Dominik, C., Demyk, K., Encrenaz, P., Falgarone, E., Fuente, A., Gerin, M., Goldsmith, P., Helmich, F., Hennebelle, P., Henning, Th., Herbst, E., Jacq, T., Kahane, C., Kama, M., Klotz, A., Langer, W., Lis, D., Lord, S., Pearson, J., Phillips, T., Saraceno, P., Schilke, P., Tielens, X., van der Tak, F., van der Wiel, M., Vastel, C., Wakelam, V., Walters, A., Wyrowski, F., Yorke, H., Borys, C., Delorme, Y., Kramer, C., Larsson, B., Mehdi, I., Ossenkopf, V. and Stutzki, J. 2010. The CHESS spectral survey of star forming regions: peering into the protostellar shock L1157-B1. I. Shock chemical complexity [Letter]. Astronomy and Astrophysics 518 , L112. 10.1051/0004-6361/201014582

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Abstract

We present the first results of the unbiased survey of the L1157-B1 bow shock, obtained with HIFI in the framework of the key program Chemical HErschel Survey of Star forming regions (CHESS). The L1157 outflow is driven by a low-mass Class 0 protostar and is considered the prototype of the so-called chemically active outflows. The bright blue-shifted bow shock B1 is the ideal laboratory for studying the link between the hot (~1000–2000 K) component traced by H2 IR-emission and the cold (~10–20 K) swept-up material. The main aim is to trace the warm gas chemically enriched by the passage of a shock and to infer the excitation conditions in L1157-B1. A total of 27 lines are identified in the 555–636 GHz region, down to an average 3σ level of 30 mK. The emission is dominated by CO(5–4) and H2O(110–101) transitions, as discussed by Lefloch et al. in this volume. Here we report on the identification of lines from NH3, H2CO, CH3OH, CS, HCN, and HCO+. The comparison between the profiles produced by molecules released from dust mantles (NH3, H2CO, CH3OH) and that of H2O is consistent with a scenario in which water is also formed in the gas-phase in high-temperature regions where sputtering or grain-grain collisions are not efficient. The high excitation range of the observed tracers allows us to infer, for the first time for these species, the existence of a warm (≥200 K) gas component coexisting in the B1 bow structure with the cold and hot gas detected from ground.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy
Uncontrolled Keywords:	ISM: individual objects: L1157; ISM: molecules; stars: formation
Additional Information:	Special Issue: Herschel: the first science highlights. Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/0004-6361/ (accessed 17/04/2014)
Publisher:	EDP Sciences
ISSN:	0004-6361
Date of First Compliant Deposit:	30 March 2016
Last Modified:	06 May 2023 05:59
URI:	https://orca.cardiff.ac.uk/id/eprint/52808

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