Dust growth and setting in protoplanetary disks and radiative transfer calculations

Murakawa, K.

doi:10.1016/j.pss.2014.05.021

Cited by 3 publications

(2 citation statements)

References 49 publications

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“…Dust settling, as well as growth, might be observed via its effect on the spectral energy distribution of a disk (Tanaka et al 2005). Tentative evidence for significant dust settling and depletion from the upper layers of the disks of T Tauri stars (ages of ∼ 10 6 yr) has been presented (Furlan et al 2006), but unambiguous detection of settling is challenging (Murakawa 2014). If settling occurs faster than the viscous accretion time of a disk (10 6 yr, Hartmann et al 1998) then grains will experience high temperatures only in a dust-rich environment.…”

Section: From Dust To Planetesimalsmentioning

confidence: 99%

What Are Little Worlds Made Of? Stellar Abundances and the Building Blocks of Planets

Gaidos

2015

ApJ

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If the photospheres of solar-type stars represent the composition of circumstellar disks from which any planets formed, spectroscopic determinations of stellar elemental abundances offer information on the composition of those planets, including smaller, rocky planets. In particular, the C/O ratio is proposed to be a key determinant of the composition of solids that condense from disk gas and are incorporated into planets. Also, planets may leave chemical signatures on the photospheres of their host stars by sequestering heavy elements, or by being accreted by the stars. The presence, absence, and composition of planets could be revealed by small differences in the relative abundances between stars. I critically examine these scenarios and show that (i) a model of Galactic chemical evolution predicts that the C/O ratio is expected to be close to the solar value and vary little between dwarf stars in the solar neighborhood; (ii) spectroscopic surveys of M dwarf stars limit the occurrence of stars with C/O 1 to < 10 −3 ; and (iii) planetesimal chemistry will be controlled by the composition of oxygen-rich dust inherited from the molecular cloud and processed in a dust-rich environment, not a gas with the stellar composition. A second generation of more reduced planetesimals could be produced by re-equilibration of material with dust-depleted gas. Finally, I discuss how minor differences in relative abundances between stars that correlate with condensation temperature can be explained by dust-gas segregation, perhaps in circumstellar disks, rather than planet formation.

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Section: From Dust To Planetesimalsmentioning

confidence: 99%

What Are Little Worlds Made Of? Stellar Abundances and the Building Blocks of Planets

Gaidos

2015

ApJ

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“…Hence, it is difficult to use these methods to calculate the radiative transfer of disks with realistic conditions. Although the radiative transfer calculations that take into account the porosity of the grains in the disks have been studied by several authors (Min et al 2012;Kirchschlager & Wolf 2014;Murakawa 2014), the high computational demands of such methods restricted these studies to the use of a simple dust model or approximations of the optical properties. Because of the limitations of radiative transfer calculations, methods of modeling observations are also limited.…”

Section: Introductionmentioning

confidence: 99%

Light Scattering by Fractal Dust Aggregates. I. Angular Dependence of Scattering

Tazaki

Tanaka

Okuzumi

et al. 2016

ApJ

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In protoplanetary disks, micron-sized dust grains coagulate to form highly porous dust aggregates. Because the optical properties of these aggregates are not completely understood, it is important to investigate how porous dust aggregates scatter light. In this study, the light scattering properties of porous dust aggregates were calculated using a rigorous method, the T-matrix method, and the results were then compared with those obtained using the Rayleigh-Gans-Debye (RGD) theory and Mie theory with the effective medium approximation (EMT). The RGD theory is applicable to moderately large aggregates made of nearly transparent monomers. This study considered two types of porous dust aggregates, ballistic cluster-cluster agglomerates (BCCAs) and ballistic particle-cluster agglomerates (BPCAs). First, the angular dependence of the scattered intensity was shown to reflect the hierarchical structure of dust aggregates; the large-scale structure of the aggregates is responsible for the intensity at small scattering angles, and their small-scale structure determines the intensity at large scattering angles. Second, it was determined that the EMT underestimates the backward scattering intensity by multiple orders of magnitude, especially in BCCAs, because the EMT averages the structure within the size of the aggregates. It was concluded that the RGD theory is a very useful method for calculating the optical properties of BCCAs.

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Cosmic Dust VI

Kimura

Kolokolova

et al. 2014

Planetary and Space Science

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Dust growth and setting in protoplanetary disks and radiative transfer calculations

Cited by 3 publications

References 49 publications

What Are Little Worlds Made Of? Stellar Abundances and the Building Blocks of Planets

What Are Little Worlds Made Of? Stellar Abundances and the Building Blocks of Planets

Light Scattering by Fractal Dust Aggregates. I. Angular Dependence of Scattering

Cosmic Dust VI

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