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Large gaps and high accretion rates in photoevaporative transition disks with a dead zone

Gárate, M; Delage, TN; Stadler, J; Pinilla, P; Birnstiel, T; Stammler, SM; Picogna, G; ... Lenz, C; + view all (2021) Large gaps and high accretion rates in photoevaporative transition disks with a dead zone. Astronomy & Astrophysics , 655 , Article A18. 10.1051/0004-6361/202141444. Green open access

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Abstract

Context. Observations of young stars hosting transition disks show that several of them have high accretion rates, despite their disks presenting extended cavities in their dust component. This represents a challenge for theoretical models, which struggle to reproduce both features simultaneously. / Aims. We aim to explore if a disk evolution model, including a dead zone and disk dispersal by X-ray photoevaporation, can explain the high accretion rates and large gaps (or cavities) measured in transition disks. / Methods. We implemented a dead zone turbulence profile and a photoevaporative mass-loss profile into numerical simulations of gas and dust. We performed a population synthesis study of the gas component and obtained synthetic images and SEDs of the dust component through radiative transfer calculations. / Results. This model results in long-lived inner disks and fast dispersing outer disks that can reproduce both the accretion rates and gap sizes observed in transition disks. For a dead zone of turbulence αdz = 10-4and an extent rdz = 10AU, our population synthesis study shows that 63% of our transition disks are still accreting with Mg ≥ 10-11M⊙ yr-1after opening a gap. Among those accreting transition disks, half display accretion rates higher than 5.0 × 10-10M⊙ yr-1. The dust component in these disks is distributed in two regions: in a compact inner disk inside the dead zone, and in a ring at the outer edge of the photoevaporative gap, which can be located between 20 and 100AU. Our radiative transfer calculations show that the disk displays an inner disk and an outer ring in the millimeter continuum, a feature that resembles some of the observed transition disks. / Conclusions. A disk model considering X-ray photoevaporative dispersal in combination with dead zones can explain several of the observed properties in transition disks, including the high accretion rates, the large gaps, and a long-lived inner disk at millimeter emission.

Type: Article
Title: Large gaps and high accretion rates in photoevaporative transition disks with a dead zone
Open access status: An open access version is available from UCL Discovery
DOI: 10.1051/0004-6361/202141444
Publisher version: http://dx.doi.org/10.1051/0004-6361/202141444
Language: English
Additional information: Copyright © M. Gárate et al. 2021. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Keywords: accretion, accretion disks; protoplanetary disks; hydrodynamics; methods: numerical
UCL classification: UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL
URI: https://discovery.ucl.ac.uk/id/eprint/10153960
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