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CCS and NH_3 Emission Associated with Low-Mass Young Stellar Objects

de Gregorio-Monsalvo, Itziar and Gómez, José F. and Suárez, Olga and Kuiper, Thomas B. H. and Rodríguez, Luis F. and Jiménez-Bailón, Elena (2006) CCS and NH_3 Emission Associated with Low-Mass Young Stellar Objects. Astrophysical Journal, 642 (1). pp. 319-329. ISSN 0004-637X. doi:10.1086/500657.

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In this work we present a sensitive and systematic single-dish survey of CCS emission (complemented with ammonia observations) at 1 cm, toward a sample of low- and intermediate-mass young star-forming regions known to harbor water maser emission, made with NASA's 70 m antenna at Robledo de Chavela, Spain. Out of the 40 star-forming regions surveyed in the CCS (2_(1)-1_(0)) line, only six low-mass sources show CCS emission: one transitional object between the prestellar and protostellar Class 0 phase (GF9-2), three Class 0 protostars (L1448-IRS3, L1448C, and B1-IRS), a Class I source (L1251A), and a young T Tauri star (NGC 2071 North). Since CCS is considered an "early-time" (≲10^5 yr) molecule, we explain these results by either proposing a revision of the classification of the age of NGC 2071 North and L1251A, or suggesting the possibility that the particular physical conditions and processes of each source affect the destruction/production of the CCS. No statistically significant relationship was found between the presence of CCS and parameters of the molecular outflows and their driving sources. Nevertheless, we found a significant relationship between the detectability of CCS and the ammonia peak intensity (higher in regions with CCS), but not with its integrated intensity. This tendency may suggest that the narrower ammonia line widths in the less turbulent medium associated with younger cores may compensate for the differences in ammonia peak intensity, rendering differences in integrated intensity negligible. From the CCS detection rate we derive a lifetime of this molecule of ≃(0.7-3) × 10^4 yr in low-mass star-forming regions.

Item Type:Article
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Kuiper, Thomas B. H.0000-0003-1798-4918
Rodríguez, Luis F.0000-0003-2737-5681
Additional Information:© 2006 American Astronomical Society. Received 2005 October 14; accepted 2005 December 22. J. F. G. is supported by grant AYA2005-08523-C03-03 of the Spanish MEC and by Junta deAndalucía (TIC-126). O. S. is partially supported by grant AYA2003-09499 of the MEC. E. J. acknowledges partial support by AYA2004-08260-C03-03 of the MEC. The work by T. B.H. K. was done at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration. L. F. R. acknowledges support from DGAPA, UNAM, and CONACyT, Mexico. I. d. G. acknowledges the support of a Calvo Rodés Fellowship from the Instituto Nacional de Técnica Aeroespacial (INTA). We are thankful to Jesús Calvo, Cristina García, Esther Moll, Pablo Perez, and the operators at the Madrid Deep Space Communication Complex (MDSCC) for their help before and during the observations at Robledo. This paper is based on observations taken during ‘‘host-country’’ allocated time at Robledo de Chavela; this time is managed by the Laboratorio de Astrofísica Espacial y Física Fundamental (LAEFF) of INTA, under agreement with the National Aeronautics and Space Administration/Ingeniería y Servicios Aeroespaciales (NASA /INSA). We would also like to thank our anonymous referee, whose valuable comments have greatly improved the quality of this paper.
Funding AgencyGrant Number
Ministerio de Educación y Ciencia (MEC)AYA2005-08523-C03-03
Junta de AndalucíaTIC-126
Ministerio de Educación y Ciencia (MEC)AYA2003-09499
Ministerio de Educación y Ciencia (MEC)AYA2004-08260-C03-03
Consejo Nacional de Ciencia y Tecnología (CONACYT)UNSPECIFIED
Instituto Nacional de Técnica Aeroespacial (INTA)UNSPECIFIED
Subject Keywords:astrochemistry; ISM: clouds; ISM: evolution; ISM: molecules; stars: formation; stars: pre-main sequence
Issue or Number:1
Record Number:CaltechAUTHORS:20110408-114350170
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Official Citation:CCS and NH_3 Emission Associated with Low-Mass Young Stellar Objects Itziar de Gregorio-Monsalvo et al. 2006 ApJ 642 319
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:23255
Deposited On:10 Apr 2011 01:10
Last Modified:09 Nov 2021 16:12

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