Herschel-PACS spectroscopy of the intermediate mass protostar NGC7129 FIRS 2 - Astrophysics > Astrophysics of GalaxiesReport as inadecuate




Herschel-PACS spectroscopy of the intermediate mass protostar NGC7129 FIRS 2 - Astrophysics > Astrophysics of Galaxies - Download this document for free, or read online. Document in PDF available to download.

Abstract: Aims: We present preliminary results of the first Herschel spectroscopicobservations of NGC7129 FIRS2, an intermediate mass star-forming region. Weattempt to interpret the observations in the framework of an in-fallingspherical envelope. Methods: The PACS instrument was used in line spectroscopymode R=1000-5000 with 15 spectral bands between 63 and 185 microns. Thisprovided good detections of 26 spectral lines seen in emission, including linesof H2O, CO, OH, O I, and C II. Results: Most of the detected lines,particularly those of H2O and CO, are substantially stronger than predicted bythe spherical envelope models, typically by several orders of magnitude. Inthis paper we focus on what can be learned from the detected CO emission lines.Conclusions: It is unlikely that the much stronger than expected line emissionarises in the spherical envelope of the YSO. The region hot enough to producesuch high excitation lines within such an envelope is too small to produce theamount of emission observed. Virtually all of this high excitation emissionmust arise in structures such as as along the walls of the outflow cavity withthe emission produced by a combination of UV photon heating and-ornon-dissociative shocks.



Author: M. Fich, D. Johnstone, T.A. van Kempen, C. McCoey, A. Fuente, P. Caselli, L.E. Kristensen, R. Plume, J. Cernicharo, G.J. Herczeg,

Source: https://arxiv.org/







Related documents