# Reduction of the maximum mass-loss rate of OH/IR stars due to unnoticed binary interaction

## TL;DR

This paper reveals that binary interactions in OH/IR stars create spiral structures that mimic superwind phases, leading to a revised understanding of the maximum mass-loss rate during the AGB phase and resolving longstanding observational discrepancies.

## Contribution

The study demonstrates that binary interactions can produce features resembling superwinds, significantly revising the maximum mass-loss rate estimates for AGB stars.

## Key findings

- Detection of spiral structures indicating binary systems.
- Hydrodynamical simulations show binary effects mimic superwind phases.
- Revised maximum mass-loss rate consistent with single-scattering limit.

## Abstract

In 1981, the idea of a superwind that ends the life of cool giant stars was proposed. Extreme OH/IR-stars develop superwinds with the highest mass-loss rates known so far, up to a few 10^(-4) Msun/yr, informing our understanding of the maximum mass-loss rate achieved during the Asymptotic Giant Branch (AGB) phase. A condundrum arises whereby the observationally determined duration of the superwind phase is too short for these stars to become white dwarfs. Here, we report on the detection of spiral structures around two cornerstone extreme OH/IR-stars, OH26.5+0.6 and OH30.1-0.7, identifying them as wide binary systems. Hydrodynamical 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 around the single-scattering radiation-pressure limit of a few 10^(-5) Msun/yr. This brings about crucial implications for nucleosynthetic yields, planet survival, and the wind-driving mechanism.