The salty emission of the intermediate-mass AGB star OH 30.1-0.7
Journal article, 2024
We analyse continuum and molecular emission, observed with Atacama Large Millimetre/submillimetre Array, from the dust-enshrouded intermediate-mass asymptotic giant branch (AGB) star OH 30.1-0.7. We find a secondary peak in the continuum maps, 'feature B', separated by 4.6 arcsec from the AGB star, which corresponds to a projected separation of 1.8 x 10(4) au, placing a lower limit on the physical separation. This feature is most likely composed of cold dust and is likely to be ejecta associated with the AGB star, though we cannot rule out that it is a background object. The molecular emission we detect includes lines of CO, SiS, CS, SO2, NS, NaCl, and KCl. We find that the NS emission is off centre and arranged along an axis perpendicular to the direction of feature B, indicative of a UV-emitting binary companion (e.g. a G-type main sequence star or hotter), perhaps on an eccentric orbit, contributing to its formation. However, the NaCl and KCl emission constrain the nature of that companion to not be hotter than a late B-type main-sequence star. We find relatively warm emission arising from the inner wind and detect several vibrationally excited lines of SiS (upsilon=1), NaCl (up to upsilon=4), and KCl (up to upsilon=2), and emission from low-energy levels in the mid to outer envelope, as traced by SO2. The CO emission is abruptly truncated around 3.5 arcsec or 14 000 au from the continuum peak, suggesting that mass loss at a high rate may have commenced as little as 2800 yr ago.
stars: AGB and post-AGB
stars: individual: OH 30.1-0.7
circumstellar matter
Author
T. Danilovich
Monash University
KU Leuven
All Sky Astrophys 3 Dimens ASTRO 3D
A. M. S. Richards
University of Manchester
M. Van de Sande
Leiden University
C. A. Gottlieb
Harvard-Smithsonian Center for Astrophysics
T. J. Millar
Queen's University Belfast
A. I. Karakas
ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)
Monash University
H. S. P. Mueller
University of Cologne
Kay Justtanont
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
J. M. C. Plane
University of Leeds
S. Etoka
University of Manchester
S. H. J. Wallstroem
KU Leuven
L. Decin
University of Leeds
KU Leuven
D. Engels
University of Hamburg
M. A. T. Groenewegen
Observatoire royal de Belgique
F. Kerschbaum
University of Vienna
Theo Khouri
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
A. de Koter
University of Amsterdam
Hans Olofsson
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
C. Paladini
European Southern Observatory Santiago
R. J. Stancliffe
University of Bristol
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 536 1 684-713Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1093/mnras/stae2584