ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars. Motivation, sample, calibration, and initial results
MONTARGÈS, M.
Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics [LESIA]
Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics [LESIA]
KERVELLA, P.
Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics [LESIA]
< Leer menos
Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics [LESIA]
Idioma
en
Article de revue
Este ítem está publicado en
Astronomy and Astrophysics - A&A. 2022, vol. 660
EDP Sciences
Resumen en inglés
This overview paper presents ATOMIUM, a Large Programme in Cycle 6 with the Atacama Large Millimeter/submillimeter Array (ALMA). The goal of ATOMIUM is to understand the dynamics and the gas phase and dust formation chemistry ...Leer más >
This overview paper presents ATOMIUM, a Large Programme in Cycle 6 with the Atacama Large Millimeter/submillimeter Array (ALMA). The goal of ATOMIUM is to understand the dynamics and the gas phase and dust formation chemistry in the winds of evolved asymptotic giant branch (AGB) and red supergiant (RSG) stars. A more general aim is to identify chemical processes applicable to other astrophysical environments. Seventeen oxygen-rich AGB and RSG stars spanning a range in (circum)stellar parameters and evolutionary phases were observed in a homogeneous observing strategy allowing for an unambiguous comparison. Data were obtained between 213.83 and 269.71 GHz at high (∼0″.025-0″.050), medium (∼0″.13-0″.24), and low (∼1″) angular resolution. The sensitivity per ∼1.3 km s<SUP>−1</SUP> channel was 1.5-5 mJy beam<SUP>−1</SUP>, and the line-free channels were used to image the millimetre wave continuum. Our primary molecules for studying the gas dynamics and dust formation are CO, SiO, AlO, AlOH, TiO, TiO<SUB>2</SUB>, and HCN; secondary molecules include SO, SO<SUB>2</SUB>, SiS, CS, H<SUB>2</SUB>O, and NaCl. The scientific motivation, survey design, sample properties, data reduction, and an overview of the data products are described. In addition, we highlight one scientific result - the wind kinematics of the ATOMIUM sources. Our analysis suggests that the ATOMIUM sources often have a slow wind acceleration, and a fraction of the gas reaches a velocity which can be up to a factor of two times larger than previously reported terminal velocities assuming isotropic expansion. Moreover, the wind kinematic profiles establish that the radial velocity described by the momentum equation for a spherical wind structure cannot capture the complexity of the velocity field. In fifteen sources, some molecular transitions other than <SUP>12</SUP>CO v = 0 J = 2 − 1 reach a higher outflow velocity, with a spatial emission zone that is often greater than 30 stellar radii, but much less than the extent of CO. We propose that a binary interaction with a (sub)stellar companion may (partly) explain the non-monotonic behaviour of the projected velocity field. The ATOMIUM data hence provide a crucial benchmark for the wind dynamics of evolved stars in single and binary star models.< Leer menos
Palabras clave en inglés
stars: AGB and post-AGB
stars: mass-loss
circumstellar matter
binaries: general
instrumentation: interferometers
astrochemistry
Astrophysics - Solar and Stellar Astrophysics
Astrophysics - Astrophysics of Galaxies
Orígen
Importado de HalCentros de investigación