Reduction of the maximum mass-loss rate of OH/IR stars due to unnoticed binary interaction
Introductory text in journal, 2019
© 2019, The Author(s), under exclusive licence to Springer Nature Limited. In 1981, the idea of a superwind that ends the life of cool giant stars was proposed 1 . Extreme oxygen-rich giants, OH/IR stars, develop superwinds with the highest mass-loss rates known so far, up to a few 10 −4 solar masses (M ⊙ ) per year 2–12 , informing our understanding of the maximum mass-loss rate achieved during the asymptotic giant branch (AGB) phase. A conundrum arises whereby the observationally determined duration of the superwind phase is too short for these stars to lose enough mass to become white dwarfs 2–4,6,8–10 . Here we report on the detection of spiral structures around two cornerstone extreme OH/IR stars, OH 26.5 + 0.6 and OH 30.1 − 0.7, thereby identifying them as wide binary systems. Hydrodynamic simulations show that the companion’s gravitational attraction creates an equatorial density enhancement mimicking a short, extreme superwind phase, thereby solving the decades-old conundrum. This discovery restricts the maximum mass-loss rate of AGB stars to around the single-scattering radiation pressure limit of a few 10 −5 M ⊙ yr −1 . This has crucial implications for nucleosynthetic yields, planet survival and the wind-driving mechanism.
Author
L. Decin
University of Leeds
KU Leuven
W. Homan
KU Leuven
Taissa Danilovich
KU Leuven
A. de Koter
Anton Pannekoek Institute for Astronomy
KU Leuven
D. Engels
Universität Hamburg
Lbfm Waters
Netherlands Institute for Space Research (SRON)
Anton Pannekoek Institute for Astronomy
Sebastien Muller
Chalmers, Space, Earth and Environment, Onsala Space Observatory, Onsala Space Observatory, Observation Support
C. Gielen
KU Leuven
D. A. García-Hernández
University of La Laguna
Instituto Astrofisico de Canarias
R. J. Stancliffe
University of Hull
University of Birmingham
M. Van De Sande
KU Leuven
G. Molenberghs
KU Leuven
Universiteit Hasselt
F. Kerschbaum
University of Vienna
A. Zijlstra
The University of Hong Kong
University of Manchester
I. El Mellah
KU Leuven
Nature Astronomy
23973366 (eISSN)
Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Metallurgy and Metallic Materials
Infrastructure
Onsala Space Observatory
DOI
10.1038/s41550-019-0703-5