Atomic hydrogen in AGB circumstellar environments. A case study: X Her

Abstract

We report the detection of the HI line at 21 cm from the circumstellar shell around the AGB star X Her using the position-switching technique with the Nancay Radio Telescope. At the star position the line shows 2 components: (i) a broad one (FWHM ~ 13 km/s) centered at -72.2 km/s, and (ii) a narrow one (FWHM \~ 4 km/s) centered at ~ -70.6 km/s. Our map shows that the source associated to the broad component is asymmetric with material flowing preferentially towards the North-East. This source extends to ~ 10 arcmin. (~ 0.4 pc) from the star in that direction. On the other hand, the narrow component is detected only at the star position and indicates material flowing away from the observer. The total mass of atomic hydrogen is ~ 6.5 10^{-3} solar mass which, within a factor 2, agrees with the estimate obtained from IRAS data at 60 microns.

accepted for publication in MNRAS

References in corpus (4)

• Mass loss rates of a sample of irregular and semiregular M-type AGB-variables
• `Thermal' SiO radio line emission towards M-type AGB stars: a probe of circumstellar dust formation and dynamics
• High-resolution imaging of compact high-velocity clouds (II)
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Cited by in corpus (14)

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• VLA Observations of HI in the Circumstellar Envelopes of Asymptotic Giant Branch Stars
• The formation of a detached shell around the carbon star Y CVn
• X Her and TX Psc: Two cases of ISM interaction with stellar winds observed by Herschel
• HI Observations of the Asymptotic Giant Branch Star X Herculis: Discovery of an Extended Circumstellar Wake Superposed on a Compact High-Velocity Cloud
• The abundance of S- and Si-bearing molecules in O-rich circumstellar envelopes of AGB stars
• An HI Imaging Survey of Asymptotic Giant Branch Stars
• The multi-scale environment of RS Cnc from CO and HI observations
• HI and CO in the circumstellar environment of the oxygen-rich AGB star RX Lep
• A Review of AGB Mass Loss Imaging Techniques
• HI line observations of 290 evolved stars made with the Nancay Radio Telescope -- I. Data