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The impact of stellar companion UV photons on the chemistry of the circumstellar environments of AGB stars
- Source :
- Van de Sande, M & Millar, T J 2021, ' The impact of stellar companion UV photons on the chemistry of the circumstellar environments of AGB stars ', Monthly Notices of the Royal Astronomical Society, vol. 510, no. 1, pp. 1204-1222 . https://doi.org/10.1093/mnras/stab3282
- Publication Year :
- 2021
- Publisher :
- arXiv, 2021.
-
Abstract
- Spherical asymmetries are prevalent within the outflows of AGB stars. Since binary interaction with a stellar or planetary companion is thought to be the underlying mechanism behind large-scale structures, we included the effects of UV radiation originating from a stellar companion in our chemical kinetics model. The one-dimensional model provides a first approximation of its effects on the chemistry throughout the outflow. The presence of a close-by stellar companion can strongly influence the chemistry within the entire outflow. Its impact depends on the intensity of the radiation (set by the stellar radius and blackbody temperature) and on the extinction the UV radiation experiences (set by the outflow density, density structure, and assumed radius of dust formation). Parent species can be photodissociated by the companion, initiating a rich photon-driven chemistry in the inner parts of the outflow. The outcome depends on the balance between two-body reactions and photoreactions. If two-body reactions dominate, chemical complexity within the outflow increases. This can make the abundance profiles of daughters appear like those of parents, with a larger inner abundance and a gaussian decline. If photoreactions dominate, the outflow can appear molecule-poor. We model three stellar companions. The impact of a red dwarf companion is limited. Solar-like companions show the largest effect, followed by a white dwarf. A stellar companion can also lead to the formation of unexpected species. The outflow's molecular content, especially combined with abundance profiles, can indicate a stellar companion's presence. Our results pave the way for further outflow-specific (three-dimensional) model development.<br />Comment: Accepted for publication in the Monthly Notices of the Royal Astronomical Society. Main paper: 20 pages, 12 figures, 4 tables. Supplementary material: 42 pages, 66 figures, 2 tables. Revision: corrections to legibility of the label of Fig. A2
- Subjects :
- Red dwarf
Extinction (astronomy)
FOS: Physical sciences
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
circumstellar matter
Abundance (ecology)
Astrophysics::Solar and Stellar Astrophysics
Black-body radiation
Astrophysics::Galaxy Astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
Physics
astrochemistry
White dwarf
Astronomy and Astrophysics
AGB and post-AGB [Stars]
Radius
Astrophysics - Astrophysics of Galaxies
molecular processes
Stars
Astrophysics - Solar and Stellar Astrophysics
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
Outflow
Astrophysics::Earth and Planetary Astrophysics
Subjects
Details
- ISSN :
- 00358711
- Database :
- OpenAIRE
- Journal :
- Van de Sande, M & Millar, T J 2021, ' The impact of stellar companion UV photons on the chemistry of the circumstellar environments of AGB stars ', Monthly Notices of the Royal Astronomical Society, vol. 510, no. 1, pp. 1204-1222 . https://doi.org/10.1093/mnras/stab3282
- Accession number :
- edsair.doi.dedup.....33f6bb681d0e8e8b1f9ae76e62cb12d7
- Full Text :
- https://doi.org/10.48550/arxiv.2111.05053