Despin Mechanism for Protogiant Planets and Ionization State of Protogiant Planetary Disks

Takata, Toshiko; Stevenson, D. J.

doi:10.1006/icar.1996.0167

Cited by 46 publications

(77 citation statements)

References 3 publications

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“…Perna, Menou & Rauscher ). The presence of magnetic fields in the protoplanet could also lead to a transfer of its angular momentum to a circumplanetary disc due to coupling of the planetary dipole field lines to the disc fluid, as discussed in Takata & Stevenson (). Although the Takata & Stevenson derivation applies only for the very last stage of the planet formation, when its radius is only a factor of 10 larger than its final value, the mechanism they describe can lead to the decreasing of L by a factor of 3–4 in this very last phase.…”

Section: Discussionmentioning

confidence: 99%

The collapse of protoplanetary clumps formed through disc instability: 3D simulations of the pre-dissociation phase

Galvagni

Hayfield

Boley

et al. 2012

Monthly Notices of the Royal Astronomical Society

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We present 3D smoothed particle hydrodynamics simulations of the collapse of clumps formed through gravitational instability in the outer part of a protoplanetary disc. The initial conditions are taken directly from a global disc simulation, and a realistic equation of state is used to follow the clumps as they contract over several orders of magnitude in density, approaching the molecular hydrogen dissociation stage. The effects of clump rotation, asymmetries and radiative cooling are studied. Rotation provides support against fast collapse, but non‐axisymmetric modes develop and efficiently transport angular momentum outwards, forming a circumplanetary disc. This transport helps the clump reach the dynamical collapse phase, resulting from molecular hydrogen dissociation, on a thousand‐year time‐scale, which is smaller than time‐scales predicted by some previous spherical 1D collapse models. Extrapolation to the threshold of the runaway hydrogen dissociation indicates that the collapse time‐scales can be shorter than inward migration time‐scales, suggesting that clumps could survive tidal disruption and deliver a protogas giant to distances of even a few au from the central star.

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Section: Discussionmentioning

confidence: 99%

The collapse of protoplanetary clumps formed through disc instability: 3D simulations of the pre-dissociation phase

Galvagni

Hayfield

Boley

et al. 2012

Monthly Notices of the Royal Astronomical Society

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“…This occurs when the magnetic Reynold's number is high or ≫ 1. For the disk with ionization state explored by Takata & Stevenson (1996), the magnetic Reynold's number is only large (> 1) in the outer layers (greater than a few vertical scale heights where ionization is produced mainly by galactic cosmic rays), and within a few planetary radii of the planet (due to thermal ionization). The magnetic field should primarily be important in these regions.…”

Section: Accretion Disk Parametersmentioning

confidence: 99%

Do Proto‐jovian Planets Drive Outflows?

Quillen

Trilling

1998

ApJ

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We discuss the possibility that gaseous giant planets drive strong outflows during early phases of their formation. We consider the range of parameters appropriate for magneto-centrifugally driven stellar and disk outflow models and find that if the proto-Jovian planet or accretion disk had a magnetic field of ∼ > 10 Gauss and moderate mass inflow accretion rates through the disk of less than ∼ 10 −7 M J /yr that it is possible to drive an outflow. Estimates based both on scaling from empirical laws observed in proto-stellar outflows and the magneto-centrifugal disk and stellar+disk wind models suggest that winds with mass outflow rates of order 10 −8 M J /yr and velocities of order ∼ 20 km/s could be driven from proto-Jovian planets. Prospects for detection and some implications for the formation of the solar system are briefly discussed.

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“…In our picture, Io should have formed dry and its migration might have been stopped at the inner truncation radius of Jupiter's accretion disk, at a few Jupiter radii (Takata & Stevenson 1996). It did not form wet and then lose its water through tidal heating.…”

Section: Accretion and Migration Of Both Planets And Moonsmentioning

confidence: 74%

“…For any given shutdown rate, we find a linear increase in the mass of solids at the time of moon formation shutdown as a function of planetary mass, in agreement with previous simulations for the solar system giants (Canup & Ward 2006;Sasaki et al 2010 Canup & Ward (2002) discuss the contribution of planetary luminosity to the disk's energy budget, but for their computations of the gas surface densities they ignore it. 8 An inner cavity can be caused by magnetic coupling between the rotating planet and the disk (Takata & Stevenson 1996), and it can be an important aspect to explain the formation of the Galilean satellites (Sasaki et al 2010). 9 This conclusion is similar to that proposed by the ME model, but for reasons that are very different.…”

Section: Accretion and Migration Of Both Planets And Moonsmentioning

confidence: 99%

Alpha-spectrometry and fractal analysis of surface micro-images for characterisation of porous materials used in manufacture of targets for laser plasma experiments

Аушев¹,

Баринов²,

Vasin³

et al. 2015

Quantum Electron.

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Most of the exoplanets with known masses at Earth-like distances to Sun-like stars are heavier than Jupiter, which raises the question of whether such planets are accompanied by detectable, possibly habitable moons. Here we simulate the accretion disks around super-Jovian planets and find that giant moons with masses similar to Mars can form. Our results suggest that the Galilean moons formed during the final stages of accretion onto Jupiter, when the circumjovian disk was sufficiently cool. In contrast to other studies, with our assumptions, we show that Jupiter was still feeding from the circumsolar disk and that its principal moons cannot have formed after the complete photoevaporation of the circumsolar nebula. To counteract the steady loss of moons into the planet due to type I migration, we propose that the water ice line around Jupiter and super-Jovian exoplanets acted as a migration trap for moons. Heat transitions, however, cross the disk during the gap opening within ≈10 4 years, which makes them inefficient as moon traps and indicates a fundamental difference between planet and moon formation. We find that icy moons larger than the smallest known exoplanet can form at about 15-30 Jupiter radii around super-Jovian planets. Their size implies detectability by the Kepler and PLATO space telescopes as well as by the European Extremely Large Telescope. Observations of such giant exomoons would be a novel gateway to understanding planet formation, as moons carry information about the accretion history of their planets.

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Despin Mechanism for Protogiant Planets and Ionization State of Protogiant Planetary Disks

Cited by 46 publications

References 3 publications

The collapse of protoplanetary clumps formed through disc instability: 3D simulations of the pre-dissociation phase

The collapse of protoplanetary clumps formed through disc instability: 3D simulations of the pre-dissociation phase

Do Proto‐jovian Planets Drive Outflows?

Alpha-spectrometry and fractal analysis of surface micro-images for characterisation of porous materials used in manufacture of targets for laser plasma experiments

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