Published November 24, 2021
| Version v1
Journal article
ATOMIUM: halide molecules around the S-type AGB star W Aquilae
Creators
- Danilovich, T.
- van de Sande, M.
- Plane, J.
- Millar, T. J.
- Royer, P.
- Amor, M. A.
- Hammami, K.
- Decock, L.
- Gottlieb, C. A.
- Decin, L.
- Richards, A. M. S.
- de Beck, E.
- Baudry, A.
- Bolte, J.
- Cannon, E.
- de Ceuster, F.
- de Koter, A.
- Etoka, S.
- Gobrecht, D.
- Gray, M.
- Herpin, F.
- Homan, W.
- Jeste, M.
- Kervella, P.
- Khouri, T.
- Lagadec, E.
- Maes, S.
- Malfait, J.
- Mcdonald, I.
- Menten, K. M.
- Montargès, M.
- Müller, H. S. P.
- Pimpanuwat, B.
- Sahai, R.
- Wallström, S.
- Waters, L. B. F. M.
- Wong, K. T.
- Yates, J.
- Zijlstra, A.
Contributors
Others:
- Institute of Astronomy [Leuven] ; Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven)
- School of Chemistry [Leeds] ; University of Leeds
- Astrophysics Research Centre [Belfast] (ARC) ; Queen's University [Belfast] (QUB)
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications (LSAMA) ; Université de Tunis El Manar (UTM)-Faculté des Sciences Mathématiques, Physiques et Naturelles de Tunis (FST) ; Université de Tunis El Manar (UTM)
- Center for Astrophysics (emeritus), Harvard-Smithsonian, Cambridge, MA, USA
- Jodrell Bank Centre for Astrophysics (JBCA) ; University of Manchester [Manchester]
- Onsala Space Observatory (OSO) ; Chalmers University of Technology [Göteborg]
- Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB) ; Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Department of Physics and Astronomy [UCL London] ; University College of London [London] (UCL)
- Astronomical Institute Anton Pannekoek (AI PANNEKOEK) ; University of Amsterdam [Amsterdam] (UvA)
- National Astronomical Research Institute of Thailand, Thailand, puji.irawati@gmail.com
- Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA) ; Université libre de Bruxelles (ULB)
- Max-Planck-Institut für Radioastronomie (MPIFR)
- Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)) ; Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
- Observatoire de la Côte d'Azur ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)
- The Open University [Milton Keynes] (OU)
- Universität zu Köln = University of Cologne
- Jet Propulsion Laboratory (JPL) ; NASA-California Institute of Technology (CALTECH)
- SRON Netherlands Institute for Space Research (SRON)
- Institute for Mathematics, Astrophysics and Particle Physics (IMAPP) ; Radboud University [Nijmegen]
- Institut de RadioAstronomie Millimétrique (IRAM) ; Centre National de la Recherche Scientifique (CNRS)
- Laboratory for Space Research [Hong Kong] (LSR) ; The University of Hong Kong (HKU)
Description
Context. S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate but have not been studied in as much detail as their carbon- and oxygen-rich counterparts. W Aql is a nearby S-type star, with well-known circumstellar parameters, making it an ideal object for in-depth study of less common molecules.Aims. We aim to determine the abundances of AlCl and AlF from rotational lines, which have been observed for the first time towards an S-type AGB star. In combination with models based on PACS observations, we aim to update our chemical kinetics network based on these results.Methods. We analyse ALMA observations towards W Aql of AlCl in the ground and first two vibrationally excited states and AlF in the ground vibrational state. Using radiative transfer models, we determine the abundances and spatial abundance distributions of Al35Cl, Al37Cl, and AlF. We also model HCl and HF emission and compare these models to PACS spectra to constrain the abundances of these species.Results. AlCl is found in clumps very close to the star, with emission confined within 0′′.1 of the star. AlF emission is more extended, with faint emission extending 0′′.2 to 0′′.6 from the continuum peak. We find peak abundances, relative to H2, of 1.7 × 10−7 for Al35Cl, 7 × 10−8 for Al37Cl, and 1 × 10−7 for AlF. From the PACS spectra, we find abundances of 9.7 × 10−8 and ≤10−8, relative to H2, for HCl and HF, respectively.Conclusions. The AlF abundance exceeds the solar F abundance, indicating that fluorine synthesised in the AGB star has already been dredged up to the surface of the star and ejected into the circumstellar envelope. From our analysis of chemical reactions in the wind, we conclude that AlF may participate in the dust formation process, but we cannot fully explain the rapid depletion of AlCl seen inthe wind.
Abstract
International audienceAdditional details
Identifiers
- URL
- https://hal.sorbonne-universite.fr/hal-03462956
- URN
- urn:oai:HAL:hal-03462956v1
Origin repository
- Origin repository
- UNICA