Tensile Strength of Porous Dust Aggregates

Tatsuuma, Misako; Kataoka, Akimasa; Tanaka, Hidekazu

doi:10.3847/1538-4357/ab09f7

Cited by 41 publications

(52 citation statements)

References 40 publications

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“…To close this section, it is important to mention that the results of Musiolik & Wurm (2019) have been regarded as controversial by some authors. Garcia & Gonzalez (2020) point out that the results of Musiolik & Wurm (2019) disagree with the tensile strength computed numerically by Tatsuuma et al (2019). Okuzumi & Tazaki (2019) mention that Musiolik's recent experiments are inconsistent with earlier ones performed by Gundlach & Blum (2015), which showed efficient sticking of H 2 O grains for temperatures down to 100 K. In addition, missing key aspects such as porosity (Garcia & Gonzalez 2020;Krijt et al 2016) and the lack of experiments involving mixtures of silicates and ices (Choukroun et al 2020) Fig.…”

Section: Appendix A: Dependence On the Fragmentation Velocity Of Grainsmentioning

confidence: 84%

The nature of the radius valley

Venturini

Guilera

Haldemann

et al. 2020

A&A

138

117

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The existence of a radius valley in the Kepler size distribution stands as one of the most important observational constraints to understand the origin and composition of exoplanets with radii between those of Earth and Neptune. In this work we provide insights into the existence of the radius valley, first from a pure formation point of view and then from a combined formation-evolution model. We run global planet formation simulations including the evolution of dust by coagulation, drift, and fragmentation, and the evolution of the gaseous disc by viscous accretion and photoevaporation. A planet grows from a moon-mass embryo by either silicate or icy pebble accretion, depending on its position with respect to the water ice line. We include gas accretion, type I–II migration, and photoevaporation driven mass-loss after formation. We perform an extensive parameter study evaluating a wide range of disc properties and initial locations of the embryo. We find that due to the change in dust properties at the water ice line, rocky cores form typically with ∼3 M⊕ and have a maximum mass of ∼5 M⊕, while icy cores peak at ∼10 M⊕, with masses lower than 5 M⊕ being scarce. When neglecting the gaseous envelope, the formed rocky and icy cores account naturally for the two peaks of the Kepler size distribution. The presence of massive envelopes yields planets more massive than ∼10 M⊕ with radii above 4 R⊕. While the first peak of the Kepler size distribution is undoubtedly populated by bare rocky cores, as shown extensively in the past, the second peak can host half-rock–half-water planets with thin or non-existent H-He atmospheres, as suggested by a few previous studies. Some additional mechanisms inhibiting gas accretion or promoting envelope mass-loss should operate at short orbital periods to explain the presence of ∼10–40 M⊕ planets falling in the second peak of the size distribution.

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Section: Appendix A: Dependence On the Fragmentation Velocity Of Grainsmentioning

confidence: 84%

The nature of the radius valley

Venturini

Guilera

Haldemann

et al. 2020

A&A

138

117

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“…Based on the OSIRIS images, the tensile strength of comet 67P is estimated (Groussin et al 2015;Basilevsky et al 2016). Recently, Tatsuuma et al (2019) studied the tensile strength of dust aggregates and found that the tensile strength of comet 67P is reproduced when the monomer radius is between 3.3 − 220 µm. Hence, sub-millimeter-sized solid spheres are candidates to explain the measured tensile strength.…”

Section: Comparison With Cometary Dust In the Solar Systemmentioning

confidence: 99%

Unveiling Dust Aggregate Structure in Protoplanetary Disks by Millimeter-wave Scattering Polarization

Tazaki

Tanaka

Kataoka

et al. 2019

ApJ

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Dust coagulation in a protoplanetary disk is the first step of planetesimal formation. However, the pathway from dust aggregates to planetesimals remains unclear. Both numerical simulations and laboratory experiments have suggested the importance of dust structure in planetesimal formation, but it is not well constrained by observations. We study how the dust structure and porosity alters polarimetric images at millimeter wavelength by performing 3D radiative transfer simulations. Aggregates with different porosity and fractal dimension are considered. As a result, we find that dust aggregates with lower porosity and/or higher fractal dimension are favorable to explain the observed millimeter-wave scattering polarization of disks. Although we cannot rule out the presence of aggregates with extremely high porosity, a population of dust particles with relatively compact structure is at least necessary to explain polarized-scattered waves. In addition, we show that particles with moderate porosity show weak wavelength dependence of scattering polarization, indicating that multi-wavelength polarimetry is useful to constrain dust porosity. Finally, we discuss implications for dust evolution and planetesimal formation in disks.

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“…As an example model, adopting a simple size dependence on the tensile strength normalization ofσ = (a eff /1 µm) −3 results in a smooth transition fromσ = 15 for the 0.4 µm case toσ = 0.6 for the 1.2 µm case. For comparison, the size-dependent tensile strength of micron-to-millimeter-scale aggregates follows, according to numerical simulations (Tatsuuma 2019), aσ = (a eff /1 µm) −2 law. The example model overestimates tensile strengths given by both the microcrack theory and numerical simulations of aggregates, as the smallest particles are composed of two monomers.…”

Section: Spectral Bluing By Disruption Processesmentioning

confidence: 98%

Rotational Disruption of Nonspherical Cometary Dust Particles by Radiative Torques

Herranen

2020

ApJ

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Rigorous statistical numerical analysis of the response of a nonspherical dust particle ensemble composed of aggregates of astronomical silicate is presented. It is found that the rotational disruption mechanism is not only likely to occur but to be a key element in explaining many separate observations of cometary dust. Namely, radiative torques are shown to spin-up and align cometary dust within the timescales of cometary activity. Additionally, the radiative torque alignment and disruption mechanisms within certain conditions are shown to be consistent with observations of rapid polarization of dust and spectral bluing of dust. The results indicate that radiative torques should be taken into account nearly universally when considering the evolution of cometary dust.

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Tensile Strength of Porous Dust Aggregates

Cited by 41 publications

References 40 publications

The nature of the radius valley

The nature of the radius valley

Unveiling Dust Aggregate Structure in Protoplanetary Disks by Millimeter-wave Scattering Polarization

Rotational Disruption of Nonspherical Cometary Dust Particles by Radiative Torques

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