Time evolution of a viscous protoplanetary disk with a free geometry: Toward a more self-consistent picture
- Laboratoire AIM-LADP, Université Paris Diderot/CEA/CNRS, F-91191 Gif sur Yvette (France)
Observations of protoplanetary disks show that some characteristics seem recurrent, even in star formation regions that are physically distant such as surface mass density profiles varying as r {sup –1} or aspect ratios of about 0.03-0.23. Accretion rates are also recurrently found around 10{sup –8}-10{sup –6} M {sub ☉} yr{sup –1} for disks that have already evolved. Several models have been developed in order to recover these properties. However, most of them usually simplify the disk geometry if not its mid-plane temperature. This has major consequences for modeling the disk evolution over millions of years and consequently planet migration. In the present paper, we develop a viscous evolution hydrodynamical numerical code that simultaneously determines the disk photosphere geometry and the mid-plane temperature. We then compare our results of long-term simulations with similar simulations of disks with a constrained geometry along the Chiang and Goldreich prescription (d lnH/d lnr = 9/7). We find that the constrained geometry models provide a good approximation of the disk surface density evolution. However, they differ significantly regarding the temperature-time evolution. In addition, we find that shadowed regions naturally appear at the transition between viscously dominated and radiation-dominated regions that falls in the region of planetary formation. We show that χ (photosphere height to pressure scale height ratio) cannot be considered a constant, which is consistent with the findings of Watanabe and Lin. Comparisons with observations show that all disks naturally evolve toward a shallow surface density disk (Σ∝r {sup –1}). The mass flux across the disk typically stabilizes in about 1 Myr.
- OSTI ID:
- 22357027
- Journal Information:
- Astrophysical Journal, Vol. 786, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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