The Effect of Internal Dissipation and Surface Irradiation on the Structure of Disks and the Location of the Snow Line around Sun-like Stars

By P. Garaud, D. Lin. 2006

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In theory of accretion disks, angular momentum and mass transfer are associated with the generation of energy through viscous dissipation. In the construction of SED models of protostellar disks, the stellar irradiation is usually assumed to be the dominant heating source. Here we construct a new set of self-consistent analytical disk models by taking into account both sources of thermal energy and the thermal structure of the disk across the midplane. We deduce a set of general formulae for the relationship between the mass accretion rate and the surface density profile. We apply it to determine the structure of protostellar disks under a state of steady accretion and derive the radial distribution of surface density and midplane temperature. The incorporation of the viscous heating in our model reduces the disk flaring angle and leads to lower photospheric temperatures than previously thought. Around T Tauri stars, the snow line can evolve from outside 10 AU during FU Orionis outbursts, to 2 AU during the quasi-steady accretion phase, to 0.7 AU when the accretion rate falls to about 10-9 M☉ yr-1, and finally reexpand beyond 2.2 AU during the protostellar-to-debris disk transition. The nonmonotonous evolution of the snow line may lead to the observed isotopic composition of water on both Venus and Earth. We also infer the presence of a marginally opaque, isothermal region with a surface density distribution similar to that of the MSN model. With a 40% higher temperature than that in the region immediately within, this transition may lead to an upturn in the SEDs in the MIR (24-70 μm) wavelength range. The optically thin, outermost regions of the disk have a shallow surface density profile of the dust that is consistent with millimeter observations of spatially resolved disks.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/883460b4cf9f3a62ed7e15ca0b7559919cc3fdc9

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Citations in the corpus

TOWARD A DETERMINISTIC MODEL OF PLANETARY FORMATION. VI. DYNAMICAL INTERACTION AND COAGULATION OF MULTIPLE ROCKY EMBRYOS AND SUPER-EARTH SYSTEMS AROUND SOLAR-TYPE STARS (2010, methodology): “(3) The magnitude of aice may be modified by the local viscous dissipation (Lecar et al. 2006) and stellar irradiation (Chiang & Goldreich 1997; Garaud & Lin 2007).”
Stable-isotopic anomalies and the accretionary assemblage of the Earth and Mars: A subordinate role for carbonaceous chondrites (2011, background): “In the context of the early solar system, one obvious and fundamental potential divergence between two modes of origin is spatial, between the inner solar system (sunward relative to Jupiter) and the outer solar system.”
Fossilized condensation lines in the Solar System protoplanetary disk (2015, background): “Hueso and Guillot (2005), Davis (2005), Garaud and Lin (2007), Oka et al. (2011), Bitsch et al. (2014a, 2015a) and Baillié et al. (2015) considered viscous heating also and introduced temperature dependent opacities with increasingly sophisticated prescriptions.”
Astrochemistry and compositions of planetary systems (2020, background): “2016), and when it falls below ∼10−8 M /yr the snowline is predicted to move interior to 1 AU (Garaud and Lin 2007; Oka et al. 2011).”
The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present (2016, background): “A111, page 2 of 18 Models for the Sun’s early evolution suggest that the Solar System’s snow line may have spent time as close in as 1 AU (e.g., Sasselov & Lecar 2000; Garaud & Lin 2007).”
A Decreased Probability of Habitable Planet Formation around Low-Mass Stars (2007, background): “Most disk models that include viscous and irradiation heating give α between about 1/2 and 1 for the inner disk (e.g. D’Alessio et al. 1998; Garaud & Lin 2007, Dullemond et al. 2007), and high-resolution submillimeter observations suggest α between 1/2 and 1 in the outer disk (Mundy et al. 2000,…”
Planet Formation around Stars of Various Masses: The Snow Line and the Frequency of Giant Planets (2007, background): “As the disk temperature evolves with time, movement of the snow line may therefore influence the properties of theoretical planetary systems (e.g. Kennedy et al. 2006; Garaud & Lin 2007).”