Title: Effects of photoevaporation on protoplanetary disc ‘isochrones’

Abstract

ABSTRACT Protoplanetary discs are the site of star and planet formation, and their evolution and consequent dispersal deeply affect the formation of planetary systems. In the standard scenario they evolve on time-scales ∼Myr due to the viscous transport of angular momentum. The analytical self-similar solution for their evolution predicts specific disc isochrones in the accretion rate–disc mass plane. However, photoevaporation by radiation emitted by the central star is likely to dominate the gas disc dispersal of the innermost region, introducing another (shorter) time-scale for this process. In this paper, we include the effect of internal (X and EUV) photoevaporation on the disc evolution, finding numerical solutions for a population of protoplanetary discs. Our models naturally reproduce the expected quick dispersal of the inner region of discs when their accretion rates match the rate of photoevaporative mass loss, in line with previous studies. We find that photoevaporation preferentially removes the lightest discs in the sample. The net result is that, counter-intuitively, photoevaporation increases the average disc mass in the sample, by dispersing the lightest discs. At the same time, photoevaporation also reduces the mass accretion rate by cutting the supply of material from the outer to the inner disc. In amore » purely viscous framework, this would be interpreted as the result of a longer viscous evolution, leading to an overestimate of the disc age. Our results thus show that photoevaporation is a necessary ingredient to include when interpreting observations of large disc samples with measured mass accretion rates and disc masses. Photoevaporation leaves a characteristic imprint on the shape of the isochrone. Accurate data of the accretion rate–disc mass plane in the low disc mass region therefore give clues on the typical photoevaporation rate.« less

Authors:

Somigliana, Alice  ^[1];

• Search DOE PAGES for author "Somigliana, Alice"
• Search DOE PAGES for ORCID "0000-0003-2090-2928"

Toci, Claudia  ^[2];

• Search DOE PAGES for author "Toci, Claudia"
• Search DOE PAGES for ORCID "0000-0002-6958-4986"

Lodato, Giuseppe  ^[3];

• Search DOE PAGES for author "Lodato, Giuseppe"
• Search DOE PAGES for ORCID "0000-0002-2357-7692"

Rosotti, Giovanni  ^[4];

• Search DOE PAGES for author "Rosotti, Giovanni"
• Search DOE PAGES for ORCID "0000-0003-4853-5736"

Manara, Carlo F.  ^[5]

• Search DOE PAGES for author "Manara, Carlo F."
• Search DOE PAGES for ORCID "0000-0003-3562-262X"

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+ Show Author Affiliations

1. Dipartimento di Fisica, Universitá degli Studi di Milano, Via Giovanni Celoria 16, I-20133 Milano, Italy
2. INAF – Osservatorio Astronomico di Brera, Via Brera 28, I-20121 Milano, Italy
3. Dipartimento di Fisica, Universitá degli Studi di Milano, Via Giovanni Celoria 16, I-20133 Milano, Italy, INAF – Osservatorio Astronomico di Brera, Via Brera 28, I-20121 Milano, Italy
4. Leiden Observatory, Leiden University, PO Box 9531, NL-2300 RA Leiden, the Netherlands
5. European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München, Germany

Publication Date:

Wed Dec 11 00:00:00 EST 2019

Sponsoring Org.:

USDOE

OSTI Identifier:

1581852

Resource Type:

Published Article

Journal Name:

Monthly Notices of the Royal Astronomical Society

Additional Journal Information:

Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 492 Journal Issue: 1; Journal ID: ISSN 0035-8711

Publisher:

Oxford University Press

Country of Publication:

United Kingdom

Language:

English