# Post main sequence evolution of icy minor planets II: water retention and white dwarf pollution around massive progenitor stars

## TL;DR

This study investigates how the mass and metallicity of progenitor stars influence water retention in icy minor planets, affecting white dwarf pollution and providing predictions for future observational tests.

## Contribution

It introduces a comprehensive analysis of water retention in icy bodies across various star masses and metallicities, highlighting the importance of progenitor mass in water preservation.

## Key findings

- Lower-mass progenitors retain more water.
- Water retention is less affected by metallicity.
- Water-rich minor planets are closer to WDs around lower-mass progenitors.

## Abstract

Most studies suggest the pollution of white dwarf (WD) atmospheres arises from accretion of minor planets, but the exact properties of polluting material, and in particular the evidence for water in some cases are not yet understood. Here we study the water retention of small icy bodies in exo-solar planetary systems, as their respective host stars evolve through and off the main sequence and eventually become WDs. We explore for the first time a wide range of star masses and metallicities. We find that the mass of the WD progenitor star is of crucial importance for the retention of water, while its metallicity is relatively unimportant. We predict that minor planets around lower-mass WD progenitors would retain more water in general, and would do so at closer distances from the WD, compared with high-mass progenitors. The dependence of water retention on progenitor mass and other parameters has direct implications for the origin of observed WD pollution, and we discuss how our results and predictions might be tested in the future as more observations of WDs with long cooling-ages become available.