Disc population synthesis: Decrease in the solid mass reservoir through pebble drift

Astronomy and Astrophysics, vol. 673, pp. A139

Abstract

Surveys of star-forming regions reveal that the dust mass of protoplanetary discs decreases by several orders of magnitude on timescales of a few million years. This decrease in the mass budget of solids is likely due to the radial drift of millimetre (mm) sized solids, called pebbles, induced by gas drag. However, quantifying the evolution of this dust component in young stellar clusters is difficult due to the inherent large spread in stellar masses and formation times. Therefore, we aim to model the collective evolution of a cluster to investigate the effectiveness of radial drift in clearing the discs of mm-sized particles. We use a protoplanetary disc model that provides a numerical solution for the disc formation, as well as the viscous evolution and photoevaporative clearing of the gas component, while also including the drift of particles limited in size by fragmentation. We find that discs are born with dust masses between 50 M⊕ and 1000 M⊕, for stars with masses, respectively, between 0.1 M⊙ and 1 M⊙. The majority of this initial dust reservoir is typically lost through drift before photoevaporation opens a gap in the gas disc for models both with and without strong X-ray-driven mass-loss rates. We conclude that the decrease in time of the mass locked in fragmentation-limited pebbles is consistent with the evolution of dust masses and ages inferred from nearby star-forming regions, when assuming viscous evolution rates corresponding to mean gas disc lifetimes between 3 Myr and 8 Myr.

Authors 3

1. Johan Appelgren

   Lund University

   Affiliation as printed

   Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden

2. Michiel Lambrechts

   University of Copenhagen · Lund University

   Affiliation as printed

   Center for Star and Planet Formation, GLOBE Institute, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark

   Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden

3. Nienke van der Marel Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University, P.O. Box 9531, NL-2300 RA Leiden, the Netherlands