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Title: Effects of Chemistry on Vertical Dust Motion in Early Protoplanetary Disks

Abstract

We propose the possibility of a new phenomenon affecting the settling of dust grains at the terrestrial region in early protoplanetary disks. Sinking dust grains evaporate in a hot inner region during the early stage of disk evolution, and the effects of condensation and evaporation on vertical dust settling can be significant. A 1D dust settling model considering both physical and chemical aspects is presented in this paper. Modeling results show that dust grains evaporate as they descend into the hotter interior and form a condensation front, above which dust-composing major elements, Mg, Si, and Fe, accumulate, creating a large temperature gradient. Repeated evaporation at the front inhibits grain growth, and small grain sizes elevate the opacity away from the midplane. Self-consistent calculations, including radiative heat transfer and condensation theory, suggest that the mid-disk temperature could be high enough for silicates to remain evaporated longer than previous estimates. The formation of a condensation front leads to contrasting settling behaviors between highly refractory elements, such as Al and Ca, and moderately refractory elements, such as Mg, Si, and Fe, suggesting that elemental abundance in planetesimals may not be a simple function of volatility.

Authors:
;  [1]
  1. Department of Geology and Geophysics, Yale University, New Haven, CT (United States)
Publication Date:
OSTI Identifier:
22679715
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 849; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; COSMIC DUST; ELEMENT ABUNDANCE; EVAPORATION; GRAIN GROWTH; GRAIN SIZE; HEAT TRANSFER; METEORITES; METEOROIDS; ONE-DIMENSIONAL CALCULATIONS; OPACITY; PLANETS; PROTOPLANETS; REFRACTORIES; SATELLITES; SILICATES; SIMULATION; STAR EVOLUTION; TEMPERATURE GRADIENTS

Citation Formats

Miyazaki, Yoshinori, and Korenaga, Jun. Effects of Chemistry on Vertical Dust Motion in Early Protoplanetary Disks. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8CD1.
Miyazaki, Yoshinori, & Korenaga, Jun. Effects of Chemistry on Vertical Dust Motion in Early Protoplanetary Disks. United States. doi:10.3847/1538-4357/AA8CD1.
Miyazaki, Yoshinori, and Korenaga, Jun. Wed . "Effects of Chemistry on Vertical Dust Motion in Early Protoplanetary Disks". United States. doi:10.3847/1538-4357/AA8CD1.
@article{osti_22679715,
title = {Effects of Chemistry on Vertical Dust Motion in Early Protoplanetary Disks},
author = {Miyazaki, Yoshinori and Korenaga, Jun},
abstractNote = {We propose the possibility of a new phenomenon affecting the settling of dust grains at the terrestrial region in early protoplanetary disks. Sinking dust grains evaporate in a hot inner region during the early stage of disk evolution, and the effects of condensation and evaporation on vertical dust settling can be significant. A 1D dust settling model considering both physical and chemical aspects is presented in this paper. Modeling results show that dust grains evaporate as they descend into the hotter interior and form a condensation front, above which dust-composing major elements, Mg, Si, and Fe, accumulate, creating a large temperature gradient. Repeated evaporation at the front inhibits grain growth, and small grain sizes elevate the opacity away from the midplane. Self-consistent calculations, including radiative heat transfer and condensation theory, suggest that the mid-disk temperature could be high enough for silicates to remain evaporated longer than previous estimates. The formation of a condensation front leads to contrasting settling behaviors between highly refractory elements, such as Al and Ca, and moderately refractory elements, such as Mg, Si, and Fe, suggesting that elemental abundance in planetesimals may not be a simple function of volatility.},
doi = {10.3847/1538-4357/AA8CD1},
journal = {Astrophysical Journal},
number = 1,
volume = 849,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}