Universität zu Köln

Fuente, A., Navarro, D. G., Caselli, P., Gerin, M., Kramer, C., Roueff, E., Alonso-Albi, T., Bachiller, R., Cazaux, S., Commercon, B., Friesen, R., Garcia-Burillo, S., Giuliano, B. M., Goicoechea, J. R., Gratier, P., Hacar, A., Jimenez-Serra, I, Kirk, J., Lattanzi, V, Loison, J. C., Malinen, J., Marcelino, N., Martin-Domenech, R., Munoz-Caro, G., Pineda, J., Tafalla, M., Tercero, B., Ward-Thompson, D., Trevino-Morales, S. P., Riviere-Marichalar, P., Roncero, O., Vidal, T. and Ballester, M. Y. (2019). Gas phase Elemental abundances in Molecular cloudS (GEMS) I. The prototypical dark cloud TMC 1. Astron. Astrophys., 624. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

GEMS is an IRAM 30 m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud Taurus molecular cloud (TMC) 1. Extensive millimeter observations have been carried out with the IRAM 30 m telescope (3 and 2mm) and the 40 m Yebes telescope (1.3 cm and 7 mm) to determine the fractional abundances of CO, HCO+, HCN, CS, SO, HCS+, and N2H+ in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from A(v) similar to 3 to similar to 20 mag. Two phases with differentiated chemistry can be distinguished: (i) the translucent envelope with molecular hydrogen densities of 1-5 x 10(3) cm(-3); and (ii) the dense phase, located at A(v) > 10 mag, with molecular hydrogen densities >10(4) cm(-3). Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C+/C/CO transition zone (A(v) similar to 3 mag) where C/H similar to 8 x 10(-5) and C/O similar to 0.8-1, until the beginning of the dense phase at A(v) similar to 10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate an S/H similar to (0.4-2.2) x 10(-6), an abundance similar to 7-40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S/H similar to 8 x 10(-8)). Based on our chemical modeling, we constrain the value of zeta(H2) to similar to(0.5-1.8) x 10(-16) s(-1) in the translucent cloud.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Fuente, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Navarro, D. G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Caselli, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gerin, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kramer, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Roueff, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Alonso-Albi, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bachiller, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cazaux, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Commercon, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Friesen, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Garcia-Burillo, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Giuliano, B. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Goicoechea, J. R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gratier, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hacar, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jimenez-Serra, I UNSPECIFIED UNSPECIFIED UNSPECIFIED Kirk, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lattanzi, V UNSPECIFIED UNSPECIFIED UNSPECIFIED Loison, J. C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Malinen, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Marcelino, N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Martin-Domenech, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Munoz-Caro, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pineda, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Tafalla, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Tercero, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ward-Thompson, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Trevino-Morales, S. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Riviere-Marichalar, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Roncero, O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Vidal, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ballester, M. Y. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-150561
DOI:	10.1051/0004-6361/201834654
Journal or Publication Title:	Astron. Astrophys.
Volume:	624
Date:	2019
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language POTENTIAL-ENERGY SURFACE; ROTATIONAL-EXCITATION; COMPARATIVE CHEMISTRY; INTERSTELLAR GAS; DIFFUSE CLOUDS; STAR-FORMATION; CO DEPLETION; TAURUS; SULFUR; IONIZATION Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15056