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On dust evolution in planet-forming discs in binary systems – I. Theoretical and numerical modelling: radial drift is faster in binary discs

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journal contribution
posted on 16.06.2021, 09:23 by Francesco Zagaria, Giovanni P Rosotti, Giuseppe Lodato
Many stars are in binaries or higher order multiple stellar systems. Although in recent years a large number of binaries have been proven to host exoplanets, how planet formation proceeds in multiple stellar systems has not been studied much yet from the theoretical standpoint. In this paper, we focus on the evolution of the dust grains in planet-forming discs in binaries. We take into account the dynamics of gas and dust in discs around each component of a binary system under the hypothesis that the evolution of the circumprimary and the circumsecondary discs is independent. It is known from previous studies that the secular evolution of the gas in binary discs is hastened due to the tidal interactions with their hosting stars. Here, we prove that binarity affects dust dynamics too, possibly in a more dramatic way than the gas. In particular, the presence of a stellar companion significantly reduces the amount of solids retained in binary discs because of a faster, more efficient radial drift, ultimately shortening their lifetime. We prove that how rapidly discs disperse depends both on the binary separation, with discs in wider binaries living longer, and on the disc viscosity. Although the less-viscous discs lose high amounts of solids in the earliest stages of their evolution, they are dissipated slowly, while those with higher viscosities show an opposite behaviour. The faster radial migration of dust in binary discs has a striking impact on planet formation, which seems to be inhibited in this hostile environment, unless other disc substructures halt radial drift further in. We conclude that if planetesimal formation were viable in binary discs, this process would take place on very short time-scales.

History

Citation

Monthly Notices of the Royal Astronomical Society, Volume 504, Issue 2, June 2021, Pages 2235–2252, https://doi.org/10.1093/mnras/stab985

Author affiliation

School of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Volume

504

Issue

2

Pagination

2235 - 2252

Publisher

Oxford University Press (OUP)

issn

0035-8711

eissn

1365-2966

Acceptance date

02/04/2021

Copyright date

2021

Available date

16/06/2021

Language

en