Planet formation in binary systems: A separation-dependent mechanism?

TL;DR

This paper investigates how the separation between stars in binary systems affects planet formation mechanisms, revealing that closer binaries favor disk fragmentation and produce more high-mass planets.

Contribution

It provides observational evidence linking binary separation to dominant planet formation processes and planetary outcomes.

Findings

Binaries wider than 100 AU resemble single stars in disk and planet formation.

Binaries between 5-100 AU have shorter-lived disks but can form high-mass planets.

Disk fragmentation likely dominates in binaries tighter than 100 AU.

Abstract

In this article, I examine several observational trends regarding protoplanetary disks, debris disks and exoplanets in binary systems in an attempt to constrain the physical mechanisms of planet formation in such a context. Binaries wider than about 100 AU are indistinguishable from single stars in all aspects. Binaries in the 5-100 AU range, on the other hand, are associated with shorter-lived but (at least in some cases) equally massive disks. Furthermore, they form planetesimals and mature planetary systems at a similar rate as wider binaries and single stars, albeit with the peculiarity that they predominantly produce high-mass planets. I posit that the location of a stellar companion influences the relative importance of the core accretion and disk fragmentation planet formation processes, with the latter mechanism being predominant in binaries tighter than 100 AU.