Detection of anhydrous hydrochloric acid, HCl, in IRC +10216 with the Herschel SPIRE and PACS spectrometers. Detection of HCl in IRC +10216

We report on the detection of anhydrous hydrochloric acid (hydrogen chlorine, HCl) in the carbon-rich star IRC+10216 using the spectroscopic facilities onboard the Herschel satellite. Lines from J = 1-0 up to J = 7-6 have been detected. From the observed intensities, we conclude that HCl is produced in the innermost layers of the circumstellar envelope with an abundance relative to H-2 of 5 x 10(-8) and extends until the molecules reach its photodissociation zone. Upper limits to the column densities of AlH, MgH, CaH, CuH, KH, NaH, FeH, and other diatomic hydrides have also been obtained.

[1]  S. Ott,et al.  Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy , 2010, 1005.5331.

[2]  S. J. Liu,et al.  Herschel : the first science highlights Special feature L etter to the E ditor The Herschel-SPIRE instrument and its in-flight performance , 2010 .

[3]  M. Wolfire,et al.  THE CHEMISTRY OF INTERSTELLAR MOLECULES CONTAINING THE HALOGEN ELEMENTS , 2009, 0910.1927.

[4]  M. Asplund,et al.  The chemical composition of the Sun , 2009, 0909.0948.

[5]  J. Cernicharo,et al.  A Detailed Analysis of the Dust Formation Zone of IRC +10216 Derived from Mid-Infrared Bands of C2H2 and HCN , 2007, 0709.4390.

[6]  Thomas Henning,et al.  The Photodetector Array Camera and Spectrometer (PACS) for the Herschel Space Observatory , 2004, Astronomical Telescopes + Instrumentation.

[7]  David A. Naylor,et al.  Apodizing functions for Fourier transform spectroscopy , 2007 .

[8]  T. Millar,et al.  The UMIST database for astrochemistry 2012 , 2012, 1212.6362.

[9]  J. Cernicharo,et al.  Oxygen Chemistry in the Circumstellar Envelope of the Carbon-Rich Star IRC +10216 , 2006, astro-ph/0605645.

[10]  R. S. Ram,et al.  Spectroscopic Constants, Abundances, and Opacities of the TiH Molecule , 2004, astro-ph/0411680.

[11]  S. Mikhailenko,et al.  15th Symposium on High-Resolution Molecular Spectroscopy , 2006 .

[12]  Cristina Puzzarini,et al.  Hyperfine structure of the J=1←0 transition of H35Cl and H37Cl: improved ground state parameters , 2004 .

[13]  H. Olofsson,et al.  Models of circumstellar molecular radio line emission - Mass loss rates for a sample of bright carbon stars , 2001, astro-ph/0101477.

[14]  Manfred Winnewisser,et al.  High-Temperature Infrared Measurements in the Region of the Bending Fundamental of H12C14N, H12C15N, and H13C14N , 2000 .

[15]  J. Cernicharo,et al.  A λ2 mm molecular line survey of the C-star envelope IRC+10216 , 2000 .

[16]  John E. Gizis.  M-subdwarfs: spectroscopic classification and the metallicity scale , 1997 .

[17]  Albert,et al.  Infrared Transitions of H12C14N and H12C15N between 500 and 10 000 cm-1 , 1996, Journal of molecular spectroscopy.

[18]  David L. Lambert,et al.  Vibrationally excited H2, HCl and NO+ in the diffuse clouds toward zeta Ophiuchi , 1995 .

[19]  D. Neufeld,et al.  Excitation of interstellar hydrogen chloride , 1994 .

[20]  A. Dalgarno,et al.  Interstellar Photodissociation and Photoionization Rates , 1991 .

[21]  G. Blake,et al.  Chlorine in dense interstellar clouds : the abundance of HCl in OMC-1. , 1985 .