Evolution of magnetized protoplanetary disks

Reyes-Ruiz, M.; Stepinski, T. F.

doi:10.1086/175120

Cited by 27 publications

(30 citation statements)

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“…This has been carried out in many papers (see e.g. Ruden & Lin 1986;Ruden & Pollack 1991;Reyes-Ruiz & Stepinski 1995, to cite only a few), but the detailed expressions may differ slightly from one work to another. Generally, these works have considered disks of small masses and sizes, and have neglected the gravitational potential of the disks themselves.…”

Section: Calculating Disk Propertiesmentioning

confidence: 99%

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

Hueso¹,

Guillot²

2005

A&A

295

339

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We present a one-dimensional model of the formation and viscous evolution of protoplanetary disks. The formation of the early disk is modeled as the result of the gravitational collapse of an isothermal molecular cloud. The disk's viscous evolution is integrated according to two parameterizations of turbulence: the classical α representation and a β parameterization, representative of non-linear turbulence driven by the keplerian shear. We apply the model to DM Tau and GM Aur, two classical T-Tauri stars with relatively well-characterized disks, retrieving the evolution of their surface density with time. We perform a systematic Monte-Carlo exploration of the parameter space (i.e. values of the α-β parameters, and of the temperature and rotation rate in the molecular cloud) to find the values that are compatible with the observed disk surface density distribution, star and disk mass, age and present accretion rate. We find that the observations for DM Tau require 0.001 < α < 0.1 or 2 × 10 −5 < β < 5 × 10 −4 . For GM Aur, we find that the turbulent viscosity is such that 4 × 10 −4 < α < 0.01 or 2 × 10 −6 < β < 8 × 10 −5 . These relatively large values show that an efficient turbulent diffusion mechanism is present at distances larger than ∼10 AU. This is to be compared to studies of the variations of accretion rates of T-Tauri stars versus age that mostly probe the inner disks, but also yield values of α ∼ 0.01. We show that the mechanism responsible for turbulent diffusion at large orbital distances most probably cannot be convection because of its suppression at low optical depths.

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Section: Calculating Disk Propertiesmentioning

confidence: 99%

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

Hueso¹,

Guillot²

2005

A&A

295

339

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“…In this paper we consider the evolution of the layered disc, which cannot be in a steady state (Gammie 1996, 1999; Stepinski 1999), and examine the implications for the outflow history of young stars and for the predicted disc mass. The most significant changes to the disc structure occur at the radii of greatest interest for planet formation (Reyes‐Ruiz & Stepinski 1995), and we discuss the implications for the migration of low‐mass planets, and for the eccentricity of massive planets interacting with the disc.…”

Section: Introductionmentioning

confidence: 99%

Episodic accretion in magnetically layered protoplanetary discs

Armitage¹,

Livio²,

Pringle³

2001

Monthly Notices of the Royal Astronomical Society

346

405

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We study protoplanetary disc evolution assuming that angular momentum transport is driven by gravitational instability at large radii, and magnetohydrodynamic (MHD) turbulence in the hot inner regions. At radii of the order of 1 AU such discs develop a magnetically layered structure, with accretion occurring in an ionized surface layer overlying quiescent gas that is too cool to sustain MHD turbulence. We show that layered discs are subject to a limit cycle instability, in which accretion onto the protostar occurs in bursts with an accretion rate of 10^{-5} solar masses / yr, separated by quiescent intervals where the accretion rate is 10^{-8} solar masses / yr. Such bursts could lead to repeated episodes of strong mass outflow in Young Stellar Objects. The transition to this episodic mode of accretion occurs at an early epoch (t < 1 Myr), and the model therefore predicts that many young pre-main-sequence stars should have low rates of accretion through the inner disc. At ages of a few Myr, the discs are up to an order of magnitude more massive than the minimum mass solar nebula, with most of the mass locked up in the quiescent layer of the disc at around 1 AU. The predicted rate of low mass planetary migration is reduced at the outer edge of the layered disc, which could lead to an enhanced probability of giant planet formation at radii of 1-3 AU.Comment: MNRAS, in pres

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“…Furthermore, the differential rotation of the disc can allow for large scale magnetic fields, possibly with spatiotemporal order (similar to the solar 11 year cycle; see, e.g., Parker 1979). Such a dynamo may have operated in the solar nebula and in circumstellar or protoplanetary discs (e.g., Reyes-Ruiz & Stepinski 1995). However, not much is known about the mutual interaction between a stellar magnetic field and a dynamo-generated disc field.…”

Section: Introductionmentioning

confidence: 99%

Outflows and accretion in a star-disc system with stellar magnetosphere and disc dynamo

Rekowski

Brandenburg

2004

A&A

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Abstract.The interaction between a protostellar magnetosphere and a surrounding dynamo-active accretion disc is investigated using an axisymmetric mean-field model. In all models investigated, the dynamo-generated magnetic field in the disc arranges itself such that in the corona, the field threading the disc is anti-aligned with the central dipole so that no X-point forms. When the magnetospheric field is strong enough (stellar surface field strength around 2 kG or larger), accretion happens in a recurrent fashion with periods of around 15 to 30 days, which is somewhat longer than the stellar rotation period of around 10 days. In the case of a stellar surface field strength of at least a few 100 G, the star is being spun up by the magnetic torque exerted on the star. The stellar accretion rates are always reduced by the presence of a magnetosphere which tends to divert a much larger fraction of the disc material into the wind. Both, a pressure-driven stellar wind and a disc wind form. In all our models with disc dynamo, the disc wind is structured and driven by magneto-centrifugal as well as pressure forces.

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Evolution of magnetized protoplanetary disks

Cited by 27 publications

References 0 publications

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

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

Episodic accretion in magnetically layered protoplanetary discs

Outflows and accretion in a star-disc system with stellar magnetosphere and disc dynamo

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