CCS and NH3 emission associated with low-mass young stellar objects
Por:
De Gregorio-Monsalvo I., Gómez J.F., Suárez O., Kuiper T.B.H., Rodríguez L.F., Jiménez-BAILÓN E.
Publicada:
1 ene 2006
Resumen:
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 (21-1 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" (?105 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) × 104 yr in low-mass star-forming regions. © 2006. The American Astronomical Society. All rights reserved. Printed in U.S.A.
Filiaciones:
De Gregorio-Monsalvo I.:
Laboratorio de Astrofísica Espacial y Física Fundamental (INTA), Apartado 50727, E-28080 Madrid, Spain
Gómez J.F.:
Laboratorio de Astrofísica Espacial y Física Fundamental (INTA), Apartado 50727, E-28080 Madrid, Spain
Instituto de Astrofísica de Andalucía (CSIC), Apartado 3004, E-18080 Granada, Spain
Suárez O.:
Laboratorio de Astrofísica Espacial y Física Fundamental (INTA), Apartado 50727, E-28080 Madrid, Spain
Kuiper T.B.H.:
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
Rodríguez L.F.:
Centro de Radioastronomia y Astrofísica, UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán, Mexico
Jiménez-BAILÓN E.:
XMM-Newton Science Operation Center/RSSD-ESA, Apartado 50727, E-28080 Madrid, Spain
All Open Access; Green
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