ALMA observations of the "fresh" carbon-rich AGB star TX Piscium
- Author(s)
- Magdalena Brunner, Marko Mecina, Matthias Maercker, Ernst A. Dorfi, Franz Kerschbaum, Hans Olofsson, Gioia Rau
- Abstract
Aims. The carbon-rich asymptotic giant branch (AGB) star TX Piscium (TX Psc) has been observed multiple times during multiple epochs and at different wavelengths and resolutions, showing a complex molecular CO line profile and a ring-like structure in thermal dust emission. We investigate the molecular counterpart in high resolution, aiming to resolve the ring-like structure and identify its origin. Methods. Atacama Large Millimeter/submillimeter Array (ALMA) observations have been carried out to map the circumstellar envelope (CSE) of TX Psc in CO(2-1) emission and investigate the counterpart to the ring-like dust structure. Results. We report the detection of a thin, irregular, and elliptical detached molecular shell around TX Psc, which coincides with the dust emission. This is the first discovery of a non-spherically symmetric detached shell, raising questions about the shaping of detached shells. Conclusions. We investigate possible shaping mechanisms for elliptical detached shells and find that in the case of TX Psc, stellar rotation of 2 km/s can lead to a non-uniform mass-loss rate and velocity distribution from stellar pole to equator, recreating the elliptical CSE. We discuss the possible scenarios for increased stellar momentum, enabling the rotation rates needed to reproduce the ellipticity of our observations, and come to the conclusion that momentum transfer of an orbiting object with the mass of a brown dwarf would be sufficient.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Chalmers University of Technology, National Aeronautics & Space Administration (NASA), Catholic University of America
- Journal
- Astronomy & Astrophysics
- Volume
- 621
- No. of pages
- 11
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361/201833652
- Publication date
- 01-2019
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Keywords
- ASJC Scopus subject areas
- Astronomy and Astrophysics, Space and Planetary Science
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/5b6c575c-e470-491c-b65e-2af70939f594