The galactic rate of second and third generation disc and planet formation

TL;DR

This study estimates the occurrence rates of second and third generation discs in binary systems within the Milky Way, assessing their potential to support planet formation and providing insights into their characteristics and prevalence.

Contribution

It introduces a population synthesis model to quantify the frequency of evolved binary systems with massive discs capable of forming planets, based on Milky Way properties.

Findings

0.26% of binaries host second-generation discs

0.13% host third-generation discs

Approximately 20% of second-generation discs can form planets

Abstract

We investigate the formation of discs within binary systems where at least one component has left the main sequence. In particular we calculate the occurrence rates of systems which can host long-lived, massive discs that may be able to support the formation of planets. We synthesize a population based on Milky Way properties, using both theoretical and observational inputs to constrain key properties such as the shape of the initial mass function, binary fraction, and mass transfer physics. We predict 0.26\% of binary systems will host Second generation discs (where the primary has evolved), and 0.13\% of systems will host Third generation discs (where the secondary also evolves). For the Milky Way, this translates into 130 million and 90 million Second and Third generation systems respectively from an estimated total of 50 billion binary systems. Of these systems that form discs, we estimate approximately 20\% of Second and 3.8\% of Third generation discs have enough mass to form a planetary system. We speculate on how the process of planet formation differs in these systems from conventional planet formation in protostellar discs.