ATOMIUM: Molecular inventory of 17 oxygen-rich evolved stars observed with ALMA
Journal article, 2024
Context. The dusty winds of cool evolved stars are a major contributor of the newly synthesised material enriching the Galaxy and future generations of stars. However, the details of the physics and chemistry behind dust formation and wind launching have yet to be pinpointed. Recent spatially resolved observations show the importance of gaining a more comprehensive view of the circumstellar chemistry, but a comparative study of the intricate interplay between chemistry and physics is still difficult because observational details such as frequencies and angular resolutions are rarely comparable. Aims. Aiming to overcome these deficiencies, ATOMIUM is an ALMA Large Programme to study the physics and chemistry of the circumstellar envelopes of a diverse set of oxygen-rich evolved stars under homogeneous observing conditions at three angular resolutions between ∼0.02′1.4′. Here we summarize the molecular inventory of these sources, and the correlations between stellar parameters and molecular content. Methods. Seventeen oxygen-rich or S-Type asymptotic giant branch (AGB) and red supergiant (RSG) stars have been observed in several tunings with ALMA Band 6, targeting a range of molecules to probe the circumstellar envelope and especially the chemistry of dust formation close to the star. We systematically assigned the molecular carriers of the spectral lines and measured their spectroscopic parameters and the angular extent of the emission of each line from integrated intensity maps. Results. Across the ATOMIUM sample, we detect 291 transitions of 24 different molecules and their isotopologues. This includes several first detections in oxygen-rich AGB/RSG stars: PO v = 1, SO2 v1 = 1 and v2 = 2, and several high energy H2O transitions. We also find several first detections in S-Type AGB stars: vibrationally excited HCN v2 = 2,3 and SiS v = 4,5,6, as well as first detections of the molecules SiC, AlCl, and AlF in W Aql. Overall, we find strong correlations between the following molecular pairs: CS and SiS, CS and AlF, NaCl and KCl, AlO and SO, SO2 and SO, and SO2 and H2O; meaning both molecules tend to have more detected emission lines in the same sources. The measured isotopic ratios of Si and S are found to be consistent with previous measurements, except for an anomalously high 29Si/30Si ratio of 4 ± 1 in the RSG VX Sgr. Conclusions. This paper presents the overall molecular inventory and an initial analysis of the large ATOMIUM dataset, laying the groundwork for future work deriving molecular abundances and abundance profiles using radiative transfer modeling which will provide more rigorous tests for chemical models.
Instrumentation: interferometers
Astrochemistry
Stars: AGB and post-AGB
Line: identification
Supergiants
Circumstellar matter
Author
Sofia Wallström
KU Leuven
Taissa Danilovich
KU Leuven
ARC Centre of Excellence for All-sky Astrophysics
Monash University
H. S.P. Müller
University of Cologne
C. A. Gottlieb
Harvard-Smithsonian Center for Astrophysics
S. Maes
KU Leuven
M. Van De Sande
University of Leeds
L. Decin
University of Leeds
KU Leuven
A. M.S. Richards
University of Manchester
A. Baudry
Laboratoire d'Astrophysique de Bordeaux
J. Bolte
University of Kiel
T. Ceulemans
KU Leuven
F. De Ceuster
KU Leuven
A. de Koter
Anton Pannekoek Institute for Astronomy
KU Leuven
I. El Mellah
University of Santiago, Chile
Center for Interdisciplinary Research in Astrophysics and Space Exploration (CIRAS)
M. Esseldeurs
KU Leuven
S. Etoka
University of Manchester
D. Gobrecht
University of Gothenburg
E. Gottlieb
Harvard School of Engineering and Applied Sciences
M. Gray
University of Manchester
National Astronomical Research Institute of Thailand
F. Herpin
Laboratoire d'Astrophysique de Bordeaux
M. Jeste
Max Planck Society
D. Kee
National Solar Observatory
P. Kervella
Paris Observatory
Theo Khouri
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
E. Lagadec
Laboratoire Joseph-Louis Lagrange
J. Malfait
KU Leuven
L. Marinho
Laboratoire d'Astrophysique de Bordeaux
I. McDonald
Open University
University of Manchester
K. M. Menten
Max Planck Society
T. J. Millar
Queen's University Belfast
M. Montargès
Paris Observatory
J. A. Nuth
NASA Goddard Space Flight Center
J. M.C. Plane
University of Leeds
R. Sahai
California Institute of Technology (Caltech)
L. B.F.M. Waters
Netherlands Institute for Space Research (SRON)
Radboud University
K. T. Wong
Uppsala University
Institut de Radioastronomie Millimétrique (IRAM)
J. Yates
University College London (UCL)
A. Zijlstra
University of Manchester
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 681 A50Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202347632