eprintid: 10167340
rev_number: 7
eprint_status: archive
userid: 699
dir: disk0/10/16/73/40
datestamp: 2023-03-28 11:10:53
lastmod: 2023-03-28 11:10:53
status_changed: 2023-03-28 11:10:53
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Montargès, M
creators_name: Cannon, E
creators_name: De Koter, A
creators_name: Khouri, T
creators_name: Lagadec, E
creators_name: Kervella, P
creators_name: Decin, L
creators_name: Mcdonald, I
creators_name: Homan, W
creators_name: Waters, LBFM
creators_name: Sahai, R
creators_name: Gottlieb, CA
creators_name: Malfait, J
creators_name: Maes, S
creators_name: Pimpanuwat, B
creators_name: Jeste, M
creators_name: Danilovich, T
creators_name: De Ceuster, F
creators_name: Van De Sande, M
creators_name: Gobrecht, D
creators_name: Wallström, SHJ
creators_name: Wong, KT
creators_name: El Mellah, I
creators_name: Bolte, J
creators_name: Herpin, F
creators_name: Richards, AMS
creators_name: Baudry, A
creators_name: Etoka, S
creators_name: Gray, MD
creators_name: Millar, TJ
creators_name: Menten, KM
creators_name: Müller, HSP
creators_name: Plane, JMC
creators_name: Yates, J
creators_name: Zijlstra, A
title: The VLT/SPHERE view of the A TOMIUM cool evolved star sample: I. Overview: Sample characterization through polarization analysis
ispublished: pub
divisions: UCL
divisions: B04
divisions: C05
divisions: F48
keywords: stars: AGB and post-AGB – supergiants – stars: mass-loss – stars: imaging – circumstellar matter – stars: evolution
note: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
abstract: Context. Low- and intermediate-mass asymptotic giant stars and massive red supergiant stars are important contributors to the chemical enrichment of the Universe. They are among the most efficient dust factories of the Galaxy, harboring chemically rich circumstellar environments. Yet, the processes that lead to dust formation or the large-scale shaping of the mass loss still escape attempts at modeling. Aims. Through the ATOMIUM project, we aim to present a consistent view of a sample of 17 nearby cool evolved stars. Our goals are to unveil the dust-nucleation sites and morphologies of the circumstellar envelope of such stars and to probe ambient environments with various conditions. This will further enhance our understanding of the roles of stellar convection and pulsations, and that of companions in shaping the dusty circumstellar medium. Methods. Here we present and analyze VLT/SPHERE-ZIMPOL polarimetric maps obtained in the visible (645- 820 nm) of 14 out of the 17 ATOMIUM sources. They were obtained contemporaneously with the ALMA high spatial resolution data. To help interpret the polarized signal, we produced synthetic maps of light scattering by dust, through 3D radiative transfer simulations with the RADMC3D code. Results. The degree of linear polarization (DoLP) observed by ZIMPOL spreads across several optical filters. We infer that it primarily probes dust located just outside of the point spread function of the central source, and in or near the plane of the sky. The polarized signal is mainly produced by structures with a total optical depth close to unity in the line of sight, and it represents only a fraction of the total circumstellar dust. The maximum DoLP ranges from 0.03- 0.38 depending on the source, fractions that can be reproduced by our 3D pilot models for grains composed of olivine, melilite, corundum, enstatite, or forsterite. The spatial structure of the DoLP shows a diverse set of shapes, including clumps, arcs, and full envelopes. Only for three sources do we note a correlation between the ALMA CO ν = 0, J = 2-1 and SiO ν = 0, J = 5-4 lines, which trace the gas density, and the DoLP, which traces the dust. Conclusions. The clumpiness of the DoLP and the lack of a consistent correlation between the gas and the dust location show that, in the inner environment, dust formation occurs at very specific sites. This has potential consequences for the derived mass-loss rates and dust-to-gas ratio in the inner region of the circumstellar environment. Except for π1 Gru and perhaps GY Aql, we do not detect interactions between the circumstellar wind and the hypothesized companions that shape the wind at larger scales. This suggests that the orbits of any other companions are tilted out of the plane of the sky.
date: 2023-03-01
date_type: published
publisher: EDP Sciences
official_url: https://doi.org/10.1051/0004-6361/202245398
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2012782
doi: 10.1051/0004-6361/202245398
lyricists_name: Yates, Jeremy
lyricists_id: JAYAT84
actors_name: Flynn, Bernadette
actors_id: BFFLY94
actors_role: owner
full_text_status: public
publication: Astronomy and Astrophysics
volume: 671
article_number: A96
issn: 0004-6361
citation:        Montargès, M;    Cannon, E;    De Koter, A;    Khouri, T;    Lagadec, E;    Kervella, P;    Decin, L;                                                                                                                 ... Zijlstra, A; + view all <#>        Montargès, M;  Cannon, E;  De Koter, A;  Khouri, T;  Lagadec, E;  Kervella, P;  Decin, L;  Mcdonald, I;  Homan, W;  Waters, LBFM;  Sahai, R;  Gottlieb, CA;  Malfait, J;  Maes, S;  Pimpanuwat, B;  Jeste, M;  Danilovich, T;  De Ceuster, F;  Van De Sande, M;  Gobrecht, D;  Wallström, SHJ;  Wong, KT;  El Mellah, I;  Bolte, J;  Herpin, F;  Richards, AMS;  Baudry, A;  Etoka, S;  Gray, MD;  Millar, TJ;  Menten, KM;  Müller, HSP;  Plane, JMC;  Yates, J;  Zijlstra, A;   - view fewer <#>    (2023)    The VLT/SPHERE view of the A TOMIUM cool evolved star sample: I. Overview: Sample characterization through polarization analysis.                   Astronomy and Astrophysics , 671     , Article A96.  10.1051/0004-6361/202245398 <https://doi.org/10.1051/0004-6361%2F202245398>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10167340/1/aa45398-22.pdf