Radial mixing in protoplanetary accretion disks

Wehrstedt, M.; Gail, H. P.

doi:10.1051/0004-6361:20020058

Cited by 38 publications

(53 citation statements)

References 48 publications

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“…Figure 1 shows this viscosity as a function of initial mass and accretion rate for a solar mass star and an angular momentum representative of the early solar nebula (Cassen 1996;Wehrstedt & Gail 2002). The contours show a stronger dependence on the disk mass than on the disk accretion rate, which is consistent with the foregoing formula.…”

Section: Solution Of the Surface Densitysupporting

confidence: 76%

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A Simplified Model for an Evolving Protoplanetary Nebula

Davis¹

2003

ApJ

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The dynamic evolution of a protoplanetary nebula is investigated using analytical solutions of the surface density transport equations. Constant-and so-called -viscosity turbulence models are compared with a functional analytical model and the well-known -viscosity formulation. The model presented here is related to a number of simplified disk evolution models but is also associated with -viscosity models based on hydrodynamic generation of turbulence. The -viscosity model, heretofore used for steady state disks, is shown to be a useful approximation for disk evolution problems.

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Section: Solution Of the Surface Densitysupporting

confidence: 76%

“…Gail (2001) used a steady state version of the disk evolution equations to compute radial mixing in protoplanetary disks. Wehrstedt & Gail (2002) extended this study to unsteady evolution. Cassen (1996) used an alternate approach in his study of fractionation in the inner solar nebula.…”

Section: Introductionmentioning

confidence: 94%

A Simplified Model for an Evolving Protoplanetary Nebula

Davis¹

2003

ApJ

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“…The small fraction of amorphous pure carbon is highly refractory. This component survives up to rather high temperatures (>1000 K, see Gail 2001;Wehrstedt & Gail 2002) until it is destroyed by oxidation reactions and is finally converted into CO. The main part of the carbonaceous material is a refractory organic material probably similar to the material kerogen known from Earth, which evaporates and decomposes at several hundred K, forming gaseous hydrocarbons and a residue resembling amorphous carbon.…”

Section: Metamorphosis Of the Carbonaceous Materials In The Solar Nebulamentioning

confidence: 99%

“…We therefore add to the set of diffusion-transport-reaction equations described in Gail (2001), Wehrstedt & Gail (2002) additional equations for the new components. In cylindrical coordinates and averaged over the vertical direction, the equations take the form…”

Section: The Concentrations C (S)mentioning

confidence: 99%

Spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals

Gail

Trieloff

2017

A&A

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Context. A high fraction of carbon bound in solid carbonaceous material is observed to exist in bodies formed in the cold outskirts of the solar nebula, while bodies in the region of terrestrial planets contain only very small mass fractions of carbon. Most of the solid carbon component is lost and converted into CO during the spiral-in of matter as the Sun accretes matter from the solar nebula. Aims. We study the fate of the carbonaceous material that entered the proto-solar disc by comparing the initial carbon abundance in primitive solar system material and the abundance of residual carbon in planetesimals and planets in the asteroid belt and the terrestrial planet region. Methods. We constructed a model for the composition of the pristine carbonaceous material from observational data on the composition of the dust component in comets and of interplanetary dust particles and from published data on pyrolysis experiments. This material entered the inner parts of the solar nebula during the course of the build-up of the proto-sun by accreting matter from the proto-stellar disc. Based on a one-zone evolution model of the solar nebula, we studied the pyrolysis of the refractory and volatile organic component and the concomitant release of hydrocarbons of high molecular weight under quiescent conditions of disc evolution, while matter migrates into the central parts of the solar nebula. We also studied the decomposition and oxidation of the carbonaceous material during violent flash heating events, which are thought to be responsible for the formation of chondrules. To do this, we calculated pyrolysis and oxidation of the carbonaceous material in temperature spikes that were modeled according to cosmochemical models for the temperature history of chondrules. Results. We find that the complex hydrocarbon components of the carbonaceous material are removed from the disc matter in the temperature range between 250 and 400 K, but the amorphous carbon component survives to temperatures of 1200 K. Without efficient carbon destruction during flash-heating associated with chondrule formation, the carbon abundance of terrestrial planets, except for Mercury, would be of several percent and not as low as it is found in cosmochemical studies. Chondrule formation seems to be a crucial process for the carbon-poor composition of the material of terrestrial planets.

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“…An example of this mixture in zone I, is the presence of Triolite (FeS) at 0.15 AU with a T C = 700 K (Lodders 2003). At this distance, an important condensation of pure Fe grains and a mild condensation of pure C may also occur (Wehrstedt & Gail 2002). The zone I also contains the internal end of the migration condensation front of H 2 O particles at ∼0.8 AU coming from the external zones of the disk (Davis 2005).…”

Section: The Planetesimal Diskmentioning

confidence: 99%

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Chavero

Reza

Domingos³

et al. 2010

A&A

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The relative distribution of abundances of refractory, intermediate, and volatile elements in stars with planets can be an important tool for investigating the internal migration of a giant planet. This migration can lead to the accretion of planetesimals and the selective enrichment of the star with these elements. We report on a spectroscopic determination of the atmospheric parameters and chemical abundances of the parent stars in transiting planets . Adding data for CoRoT-3 and CoRoT-5 from the literature, we find a flat distribution of the relative abundances as a function of their condensation temperatures. For CoRoT-2, the relatively high lithium abundance and intensity of its Li i resonance line permit us to propose an age of 120 Myr, making this star one of the youngest stars with planets to date. We introduce a new methodology to investigate a relation between the abundances of these stars and the internal migration of their planets. By simulating the internal migration of a planet in a disk formed only by planetesimals, we are able, for the first time, to separate the stellar fractions of refractory, intermediate, and volatile rich planetesimals accreting onto the central star. Intermediate and volatile element fractions enriching the star are similar and much larger than those of pure refractory ones. This result is opposite to what has been considered in the literature for the accreting self-enrichment processes of stars with planets. We also show that these results are highly dependent on the model adopted for the disk distribution regions in terms of refractory, intermediate, and also volatile elements and other parameters considered. We note however, that this self-enrichment mechanism is only efficient during the first 20-30 Myr or later in the lifetime of the disk when the surface convection layers of the central star for the first time attain its minimum size configuration.

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Radial mixing in protoplanetary accretion disks

Cited by 38 publications

References 48 publications

A Simplified Model for an Evolving Protoplanetary Nebula

A Simplified Model for an Evolving Protoplanetary Nebula

Spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

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