Detection of OH Towards the Extreme Carbon Star IRC+10216

Abstract

We report the detection of the 1665 and 1667 MHz main lines of OH (hydroxyl) and upper limits on the 1612 MHz satellite line of OH towards the carbon-rich AGB star, IRC+10216. We find a beam averaged fractional abundance x(OH)~4x10^{-8}. This detection supports the identification by Melnick et al. (2001) of the 1_10-1_01 transition of water vapor with a 556.936 GHz emission feature detected towards IRC+10216, since OH is the expected photodissociation product of water vapor. The shape of the OH lines, however, differs significantly from the shape expected based on the observations of Melnick et al. (2001). Possible explanations for the anomalous shapes of the 1665 and 1667 MHz lines are discussed. The most likely explanations for the unexpected OH line shapes are either masing or an asymmetric distribution of OH molecules around IRC+10216.

arXiv commentaccepted by ApJ

References in corpus (4)

• Smoke Signals From IRC +10216: 1. Milliarcsecond Proper Motions of the Dust
• Bispectrum speckle interferometry of IRC+10216: the dynamic evolution of the innermost circumstellar environment from 1995 to 2001
• Water Vapor in Carbon-rich AGB Stars from the Vaporization of Icy Orbiting Bodies
• IRC+10216 in Action: Present Episode of Intense Mass-Loss Reconstructed by Two-Dimensional Radiative Transfer Modeling

Cited by in corpus (18)

• Oxygen Chemistry in the Circumstellar Envelope of the Carbon-Rich Star IRC+10216
• Molecular shells in IRC+10216: tracing the mass loss history
• The Transition from Atomic to Molecular Hydrogen in Interstellar Clouds: 21cm Signature of the Evolution of Cold Atomic Hydrogen in Dense Clouds
• Evolution and Mass Loss of Cool Ageing Stars: a Daedalean Story
• Detection of C3O in the low-mass protostar Elias 18
• Detection of Formaldehyde Towards the Extreme Carbon Star IRC+10216
• Other Kuiper Belts
• ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars: Motivation, sample, calibration, and initial results
• Submillimeter narrow emission lines from the inner envelope of IRC+10216
• Extrasolar comets : the origin of dust in exozodiacal disks?
• Constraints on the H2O formation mechanism in the wind of carbon-rich AGB stars
• Herschel/HIFI observations of IRC+10216: water vapor in the inner envelope of a carbon-rich AGB star
• Water vapor emission from IRC+10216 and other carbon-rich stars: model predictions and prospects for multitransition observations
• Monitor variability of millimeter lines in IRC +10216
• Chemistry in AGB stars: successes and challenges
• The Role of Ultraviolet Photons in Circumstellar Astrochemistry
• Detection of 4765 MHz OH Emission in a Pre-Planetary Nebula -- CRL 618
• Stellar masers, circumstellar envelopes, and supernova remnants