Evolution of protoplanetary disks: constraints from DM Tauri and GM Aurigae

Hueso, R.; Guillot, T.

doi:10.1051/0004-6361:20041905

Cited by 295 publications

(359 citation statements)

References 80 publications

(160 reference statements)

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“…However, considering an interstellar dust-to-gas ratio of 10 −2 , such disks contain only 15 M ⊕ of solid material, and cannot form the solar system. We take it as an indication that or the masses are underestimated (Hartmann 2008) or that, as these observations correspond to relatively older disks (1-4 Myr), the gas has already dissipated significantly (Hueso & Guillot 2005). Our model then should be representative of young disks, therefore corresponding to an early formation of relatively massive planetary embryos.…”

Section: Disk Massmentioning

confidence: 99%

Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks

Lyra¹,

Johansen

Zsom

et al. 2009

A&A

168

188

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Context. As accretion in protoplanetary disks is enabled by turbulent viscosity, the border between active and inactive (dead) zones constitutes a location where there is an abrupt change in the accretion flow. The gas accumulation that ensues triggers the Rossby wave instability, which in turn saturates into anticyclonic vortices. It has been suggested that the trapping of solids within them leads to a burst of planet formation on very short timescales. Aims. We study in the formation and evolution of the vortices in greater detail, focusing on the implications for the dynamics of embedded solid particles and planet formation. Methods. We performed two-dimensional global simulations of the dynamics of gas and solids in a non-magnetized thin protoplanetary disk with the Pencil code. We used multiple particle species of radius 1, 10, 30, and 100 cm. We computed the particles' gravitational interaction by a particle-mesh method, translating the particles' number density into surface density and computing the corresponding self-gravitational potential via fast Fourier transforms. The dead zone is modeled as a region of low viscosity. Adiabatic and locally isothermal equations of state are used. Results. The Rossby wave instability is triggered under a variety of conditions, thus making vortex formation a robust process. Inside the vortices, fast accumulation of solids occurs and the particles collapse into objects of planetary mass on timescales as short as five orbits. Because the drag force is size-dependent, aerodynamical sorting ensues within the vortical motion, and the first bound structures formed are composed primarily of similarly-sized particles. In addition to erosion due to ram pressure, we identify gas tides from the massive vortices as a disrupting agent of formed protoplanetary embryos. We find evidence that the backreaction of the drag force from the particles onto the gas modifies the evolution of the Rossby wave instability, with vortices being launched only at later times if this term is excluded from the momentum equation. Even though the gas is not initially gravitationally unstable, the vortices can grow to Q ≈ 1 in locally isothermal runs, which halts the inverse cascade of energy towards smaller wavenumbers. As a result, vortices in models without self-gravity tend to rapidly merge towards a m = 2 or m = 1 mode, while models with self-gravity retain dominant higher order modes (m = 4 or m = 3) for longer times. Non-selfgravitating disks thus show fewer and stronger vortices. We also estimate the collisional velocity history of the particles that compose the most massive embryo by the end of the simulation, finding that the vast majority of them never experienced a collision with another particle at speeds faster than 1 m s −1 . This result lends further support to previous studies showing that vortices provide a favorable environment for planet formation.

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Section: Disk Massmentioning

confidence: 99%

Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks

Lyra¹,

Johansen

Zsom

et al. 2009

A&A

168

188

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“…For a MMSN-type disk with a uniform α, v ν = 0 everywhere which is unrealistic (the disk spreads inward and outward at the same rate). When assuming Σ g ∝ r −1 , which is more commonly found in realistic disk evolutions (e.g., Hueso & Guillot 2005), v ν = −(3/2)ν/r. The negative sign indicates an inward flow.…”

Section: Rate and Geometry Of Gas Accretionmentioning

confidence: 99%

“…neglect the disk's gravity over that of the star, in which case the vertical density structure writes (e.g., Hueso & Guillot 2005):…”

Section: Introductionmentioning

confidence: 99%

“…(We note that Youdin & Lithwick (2007) extend this relation to any eddy mixing timescale with a slightly more complex dependence on τ s which is minor and not taken into account here.) We will use a fiducial value α = 10 −2 broadly compatible with measured T-Tauri accretion rates and disk observations (e.g., Hartmann et al 1998;Hueso & Guillot 2005) and simulations of magneto-rotational instability in disks (e.g., Heinemann & Papaloizou 2009;Flock et al 2013). We will also use a lower value α = 10 −4 more relevant to the turbulence inside dead zones (e.g., Okuzumi & Hirose 2011).…”

Section: Introductionmentioning

confidence: 99%

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On the filtering and processing of dust by planetesimals

Guillot

Ida

Ormel

2014

A&A

141

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Context. Circumstellar disks are known to contain a significant mass in dust ranging from micron to centimeter size. Meteorites are evidence that individual grains of those sizes were collected and assembled into planetesimals in the young solar system. Aims. We assess the efficiency of dust collection of a swarm of non-drifting planetesimals with radii ranging from 1 to 10 3 km and beyond. Methods. We calculate the collision probability of dust drifting in the disk due to gas drag by planetesimal accounting for several regimes depending on the size of the planetesimal, dust, and orbital distance: the geometric, Safronov, settling, and three-body regimes. We also include a hydrodynamical regime to account for the fact that small grains tend to be carried by the gas flow around planetesimals. Results. We provide expressions for the collision probability of dust by planetesimals and for the filtering efficiency by a swarm of planetesimals. For standard turbulence conditions (i.e., a turbulence parameter α = 10 −2 ), filtering is found to be inefficient, meaning that when crossing a minimum-mass solar nebula (MMSN) belt of planetesimals extending between 0.1 AU and 35 AU most dust particles are eventually accreted by the central star rather than colliding with planetesimals. However, if the disk is weakly turbulent (α = 10 −4 ) filtering becomes efficient in two regimes: (i) when planetesimals are all smaller than about 10 km in size, in which case collisions mostly take place in the geometric regime; and (ii) when planetary embryos larger than about 1000 km in size dominate the distribution, have a scale height smaller than one tenth of the gas scale height, and dust is of millimeter size or larger in which case most collisions take place in the settling regime. These two regimes have very different properties: we find that the local filtering efficiency x filter,MMSN scales with r −7/4 (where r is the orbital distance) in the geometric regime, but with r −1/4 to r 1/4 in the settling regime. This implies that the filtering of dust by small planetesimals should occur close to the central star and with a short spread in orbital distances. On the other hand, the filtering by embryos in the settling regime is expected to be more gradual and determined by the extent of the disk of embryos. Dust particles much smaller than millimeter size tend only to be captured by the smallest planetesimals because they otherwise move on gas streamlines and their collisions take place in the hydrodynamical regime. Conclusions. Our results hint at an inside-out formation of planetesimals in the infant solar system because small planetesimals in the geometrical limit can filter dust much more efficiently close to the central star. However, even a fully-formed belt of planetesimals such as the MMSN only marginally captures inward-drifting dust and this seems to imply that dust in the protosolar disk has been filtered by planetesimals even smaller than 1 km (not included in this study) or that it has been assembled into planetesi...

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“…object of 10 −6 M yr −1 , which is also an upper limit (Hueso & Guillot 2005). According to the turbulence limitation we discussed in the previous section, we restrict the snow border extend and growth in the mid-plane of the accretion disc.…”

Section: Proto-planetary Disksmentioning

confidence: 99%

The snow border

Marseille

Cazaux²

2011

A&A

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Context. The study of the snow line is an important topic in several domains of astrophysics, and particularly for the evolution of proto-stellar environments and the formation of planets. Aims. The formation of the first layer of ice on carbon grains requires low temperatures compared to the temperature of evaporation (T > 100 K). This asymmetry generates a zone in which bare and icy dust grains coexist. Our aim is to derive the proportion of bare grains around the theoretical snow line position for a typical low-mass protostellar disk and a massive protostar, and estimate the size of this mixing zone compared to the dust envelope size. Methods. We use Monte-Carlo simulations to describe the formation time scales of ice mantles on bare grains in protostellar disks and massive protostars environments. Then we analytically describe these two systems in terms of grain populations subject to infall and turbulence, and assume steady-state. Numerical applications use standard numbers obtained by previous observations or modelling of the astrophysical objects studied. Results. Our results show that there is an extended region beyond the snow line where icy and bare grains can coexist, in both protoplanetary disks and massive protostars. This zone is not negligible compared to the total size of the objects: on the order of 0.4 AU for proto-planetary disks and 5400 AU for high-mass protostars. Times to reach the steady-state are respectively estimated from 10 2 to 10 5 yr. Conclusions. The presence of a zone, a so-called snow border, in which bare and icy grains coexist can have a major impact on our knowledge of protostellar environments. From a theoretical point of view, the progression of icy grains to bare grains as the temperature increases, could be a realistic way to model hot cores and hot corinos. Also, in this zone, the formation of planetesimals will require the coagulation of bare and icy grains. Observationally, this zone allows high abundances of gas phase species at large scales, for massive protostars particularly, even at low temperatures (down to 50 K). This could be a critical point for the analysis of upcoming water observations by the Herschel Space Observatory.

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Evolution of protoplanetary disks: constraints from DM Tauri and GM Aurigae

Cited by 295 publications

References 80 publications

Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks

Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks

On the filtering and processing of dust by planetesimals

The snow border

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