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On dust evolution in planet-forming discs in binary systems – II. Comparison with Taurus and ρ Ophiuchus (sub-)millimetre observations: discs in binaries have small dust sizes

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journal contribution
posted on 14.09.2021, 08:51 by Francesco Zagaria, Giovanni P Rosotti, Giuseppe Lodato
The recently discovered exoplanets in binary or higher order multiple stellar systems sparked a new interest in the study of protoplanetary discs in stellar aggregations. Here, we focus on disc solids, as they make up the reservoir out of which exoplanets are assembled and dominate (sub-)millimetre disc observations. These observations suggest that discs in binary systems are fainter and smaller than in isolated systems. In addition, disc dust sizes are consistent with tidal truncation only if they orbit very eccentric binaries. In a previous study, we showed that the presence of a stellar companion hastens the radial migration of solids, shortening disc lifetime, and challenging planet formation. In this paper, we confront our theoretical and numerical results with observations: Disc dust fluxes and sizes from our models are computed at ALMA wavelengths and compared with Taurus and ρ Ophiuchus data. A general agreement between theory and observations is found. In particular, we show that the dust disc sizes are generally smaller than the binary truncation radius due to the combined effect of grain growth and radial drift: Therefore, small disc sizes do not require implausibly high eccentricities to be explained. Furthermore, the observed binary discs are compatible within 1σ with a quadratic flux–radius correlation similar to that found for single-star discs and show a close match with the models. However, the observational sample of resolved binary discs is still small and additional data are required to draw more robust conclusions on the flux–radius correlation and how it depends on the binary properties.

History

Citation

Monthly Notices of the Royal Astronomical Society, Volume 507, Issue 2, October 2021, Pages 2531–2549, https://doi.org/10.1093/mnras/stab2024

Author affiliation

School of Physics and Astronomy

Version

AM (Accepted Manuscript)

Published in

Monthly Notices of the Royal Astronomical Society

Volume

507

Issue

2

Pagination

2531 - 2549

Publisher

Oxford University Press (OUP)

issn

0035-8711

eissn

1365-2966

Acceptance date

09/07/2021

Copyright date

2021

Available date

14/09/2021

Language

en