The dispersal of protoplanetary discs - I. A new generation of X-ray photoevaporation models
Abstract
Photoevaporation of planet-forming discs by high-energy radiation from the central star is potentially a crucial mechanism for disc evolution and it may play an important role in the formation and evolution of planetary systems. We present here a new generation of X-ray photoevaporation models for solar-type stars, based on hydrodynamical simulations, which account for stellar irradiation via a significantly improved parametrization of gas temperatures, based on detailed photoionization and radiation transfer calculations. This is the first of a series of papers aiming at providing a library of models which cover the observed parameter space in stellar and disc mass, metallicity, and stellar X-ray properties. We focus here on solar-type stars (0.7 M⊙) with relatively low-mass discs (1 per cent of the stellar mass) and explore the dependence of the wind mass-loss rates on stellar X-ray luminosity. We model primordial discs and transition discs at various stages of evolution. Our two-dimensional hydrodynamical models are then used to derive simple recipes for the mass-loss rates that are suitable for one-dimensional disc evolution and/or planet formation models typically employed for population synthesis studies. Line profiles from typical wind diagnostics ([O I]6300 Å and [Ne II]12.8 μm) are also calculated for our models and found to be roughly in agreement with previous studies. Finally, we perform a population study of transition discs by means of one-dimensional viscous evolution models including our new photoevaporation prescription and find that roughly a half of observed transition discs cavities and accretion rates could be reproduced by our models.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2019
- DOI:
- 10.1093/mnras/stz1166
- arXiv:
- arXiv:1904.02752
- Bibcode:
- 2019MNRAS.487..691P
- Keywords:
-
- accretion;
- accretion discs;
- protoplanetary discs;
- circumstellar matter;
- stars: pre-main-sequence;
- X-rays: stars;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Instrumentation and Methods for Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 12 pages, 14 figures, published in MNRAS