On the location of the ice line in circumbinary discs

TL;DR

This study models the position of the ice line in circumbinary discs, highlighting the significant role of tidal heating in extending the ice line outward, which impacts the potential habitability zones in such systems.

Contribution

It introduces a simplified model that incorporates tidal heating to better understand the ice line location in circumbinary discs, a factor often neglected in previous models.

Findings

Tidal heating can significantly extend the ice line radius.

In most binaries, the ice line lies outside the inner disc radius when tidal heating is considered.

The fraction of binaries with ice lines inside the inner radius is reduced by tidal heating.

Abstract

Position of the ice line in a circumbinary disc is determined using a simplified and illustrative model. Main sources of the heat in the energy balance of the disc, i.e. heating by the turbulence, irradiation by the components of the binary and the tidal heating are considered. Our goal is to clarify role of the tidal heating in the position of the ice line. When viscous heating and irradiation of the binary are considered, ice line lies interior to the inner radius of the disc in most of the binaries represented by our parameter survey. But tidal heating significantly extends position of the ice line to a larger radius, so that a smaller fraction of the circumbinaries' population may have ice lines interior to the inner radius of the disc.