Standing on the shoulders of giants

Lyra, Wladimir; Johansen, Anders; Klahr, Hubert; Piskunov, Nikolai

doi:10.1051/0004-6361:200810797

Cited by 158 publications

(175 citation statements)

References 49 publications

(73 reference statements)

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“…These locally confined quiescent environments could decrease both the relative and radial velocities of particles, thus allowing particles possibly to either grow to larger sizes or to accumulate until gravitational instabilities become important (see Johansen et al 2007;Lyra et al 2009). These effects are not yet included in this model and will be the subject of future research.…”

Section: Discussionmentioning

confidence: 99%

Dust retention in protoplanetary disks

Birnstiel¹,

Dullemond²,

Brauer³

2009

A&A

144

141

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Context. Protoplanetary disks are observed to remain dust-rich for up to several million years. Theoretical modeling, on the other hand, raises several questions. Firstly, dust coagulation occurs so rapidly, that if the small dust grains are not replenished by collisional fragmentation of dust aggregates, most disks should be observed to be dust poor, which is not the case. Secondly, if dust aggregates grow to sizes of the order of centimeters to meters, they drift so fast inwards, that they are quickly lost. Aims. We attempt to verify if collisional fragmentation of dust aggregates is effective enough to keep disks "dusty" by replenishing the population of small grains and by preventing excessive radial drift. Methods. With a new and sophisticated implicitly integrated coagulation and fragmentation modeling code, we solve the combined problem of coagulation, fragmentation, turbulent mixing and radial drift and at the same time solve for the 1D viscous gas disk evolution. Results. We find that for a critical collision velocity of 1 m s −1 , as suggested by laboratory experiments, the fragmentation is so effective, that at all times the dust is in the form of relatively small particles. This means that radial drift is small and that large amounts of small dust particles remain present for a few million years, as observed. For a critical velocity of 10 m s −1 , we find that particles grow about two orders of magnitude larger, which leads again to significant dust loss since larger particles are more strongly affected by radial drift.

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Section: Discussionmentioning

confidence: 99%

Dust retention in protoplanetary disks

Birnstiel¹,

Dullemond²,

Brauer³

2009

A&A

144

141

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“…Mamatsashvili & Rice (2009) argues that the combined effect of self-gravity and Keplerian shear opposes the merging of vortices or destructs the large-scale vortices into smaller vortices. However, in Lyra et al (2009a), who use a setup more similar to ours both in viscosity reduction and locally isothermal equation of state, large vortices (m = 3) with Q ≈ 1 are formed at t = 75 orbits. Because in our model, (a) the energy dissipation can not occur because we omitted the energy equation; (b) the RWI is continuously driven by the fixed-shaped bump and the planet; and (c) the simulations are performed for a large number of orbits, the large-scale vortex is formed and survives.…”

Section: Strength Of the Vortexmentioning

confidence: 93%

Planet-vortex interaction: How a vortex can shepherd a planetary embryo

Ataiee

Dullemond

Kley

et al. 2014

A&A

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Context. Anti-cyclonic vortices are considered to be a favourable places for trapping dust and forming planetary embryos. On the other hand, they are massive blobs that can interact gravitationally with the planets in the disc. Aims. We aim to study how a vortex interacts gravitationally with a planet that migrates towards the vortex or with a planet that is created inside the vortex. Methods. We performed hydrodynamical simulations of a viscous locally isothermal disc using GFARGO and FARGO-ADSG. We set a stationary Gaussian pressure bump in the disc so that a large vortex is formed and maintained as a result of Rossby wave instability (RWI). After the vortex is established, we implanted a low-mass planet ([5, 1, 0.5] × 10 −6 M ) in the outer disc or inside the vortex and allowed it to migrate. We also examined the effect of vortex strength on the planet migration by doubling the height of the bump and checked the validity of the final result in the presence of self-gravity. Results. We noticed that regardless of the planet's initial position, the planet is finally locked to the RWI-created vortex in a 1:1 resonance or its migration is stopped at a larger orbital distance, in case of a stronger vortex. For the model with the weaker vortex (our standard model), we studied the effect of different parameters such as background viscosity, background surface density, mass of the planet, and different planet positions. In these models, while the trapping time and locking angle of the planet vary for different parameters, the main result, which is the planet-vortex locking, remains valid. We discovered that even a planet with a mass less than 5 × 10 −7 M comes out from the vortex and is locked to it at the same orbital distance. For a stronger vortex, both in non-selfgravitating and self-gravitating models, the planet migration is stopped far away from the radial position of the vortex. This effect can make the vortices a suitable place for continual planet formation under the condition that they save their shape during the planetary growth.

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“…Very recently, Lyra & Mac Low (2012) have performed the first MHD simulation of the inner edge of the dead zone in unstratified 3D to show the formation of this bump and the growth of the RWI in this region. The region of the ice line is also expected to form an extremum in the density and entropy profile (Kretke & Lin 2007) and could be a region of vortex formation, as well as the edge of planet gaps (Koller et al 2003;de Val-Borro et al 2007;Lyra et al 2009a;Yu et al 2010;Lin & Papaloizou 2011).…”

Section: The Rossby Wave Instabilitymentioning

confidence: 99%

Dust-trapping Rossby vortices in protoplanetary disks

Méheut¹,

Méliani²,

Varnière³

et al. 2012

A&A

110

108

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Context. One of the most challenging steps in planet formation theory is the one leading to the formation of planetesimals of kilometre size. A promising scenario involves the existence of vortices able to concentrate a large amount of dust and grains in their centres. Up to now this scenario has mostly been studied in 2D razor thin disks. A 3D study including, simultaneously, the formation and resulting dust concentration of the vortices with vertical settling, is still missing. Aims. The Rossby wave instability self-consistently forms 3D vortices, which have the unique quality of presenting a large-scale vertical velocity in their centre. Here we aim to study how this newly discovered effect can alter the dynamic evolution of the dust. Methods. We performed global 3D simulations of the RWI in a radially and vertically stratified disk using the code MPI-AMRVAC. After the growth phase of the instability, the gas and solid phases are modelled by a bi-fluid approach, where the dust is considered as a fluid without pressure. Both the drag force of the gas on the dust and the back reaction of the dust on the gas are included. Multiple grain sizes from 1 mm to 5 cm are used with a constant density distribution. Results. We obtain in a short timescale a high concentration of the largest grains in the vortices. Indeed, in 3 rotations the dust-to-gas density ratio grows from 10 −2 to unity leading to a concentration of mass up to that of Mars in one vortex. The presence of the radial drift is also at the origin of a dust pile-up at the radius of the vortices. Lastly, the vertical velocity of the gas in the vortex causes the sedimentation process to be reversed, the mm size dust is lifted and higher concentrations are obtained in the upper layer than in the midplane. Conclusions. The Rossby wave instability is a promising mechanism for planetesimal formation, and the results presented here can be of particular interest in the context of future observations of protoplanetary disks.

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Standing on the shoulders of giants

Cited by 158 publications

References 49 publications

Dust retention in protoplanetary disks

Dust retention in protoplanetary disks

Planet-vortex interaction: How a vortex can shepherd a planetary embryo

Dust-trapping Rossby vortices in protoplanetary disks

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