White Dwarfs in Wide Binary Systems as Reliable Age Calibrators

TL;DR

This paper discusses how massive white dwarfs in wide binary systems can serve as reliable age calibrators, emphasizing the need for specific instrumentation to observe these faint objects and improve age estimates.

Contribution

It highlights the potential of massive white dwarfs in wide binaries for precise age determination and outlines the observational requirements to study these faint stellar remnants.

Findings

Massive white dwarfs have negligible main-sequence progenitor lifetimes.

Observing faint white dwarfs requires specialized instrumentation.

White dwarfs in binaries can improve stellar age estimates.

Abstract

Deriving precise stellar ages is a challenging task. Consequently, age-dependent relations - such as the age-metallicity and age-velocity dispersion relations of the Milky Way, or the age-rotation-activity relation of low-mass stars - are subject to potentially large uncertainties, despite the well-defined trends observed at the population level. White dwarfs, the most common stellar remnants, follow a relatively simple and well-understood cooling process. When found in wide binary systems with main-sequence companions, they can therefore provide the much-needed precise age estimates. The total age of such systems depends not only on the white dwarf cooling time but also on the lifetime of the main-sequence progenitor. Estimating this lifetime requires knowledge of the progenitor mass, which is typically inferred by adopting an initial-to-final mass relation. However, the observational constraints on this relation are still poorly defined, introducing a source of uncertainty in white dwarf age determinations. To mitigate this issue, we focus on a large sample of massive white dwarfs (>~0.7 Msun), for which the main-sequence progenitor lifetime is negligible. These white dwarfs are intrinsically faint and therefore require specialized facilities for adequate follow-up observations. In this white paper, we outline the instrumentation requirements needed to observe the forthcoming population of massive white dwarfs in our Galaxy.