Planetesimals in Debris Disks of Sun-Like Stars

Shannon, Andrew; Wu, Yanqin

doi:10.1088/0004-637x/739/1/36

Cited by 53 publications

(32 citation statements)

References 75 publications

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“…In such a disc, collisions between planetesimals will be destructive due to the high relative velocities. Furthermore, eccentricities will remain high as ongoing stirring processes will dominate over collisional damping (Kenyon & Bromley 2004; Shannon & Wu 2011). We do note that there may be discs where the relative velocities remain low (Heng & Tremaine 2010) in which eccentricities may be continually damped by collisions.…”

Section: Discussionmentioning

confidence: 99%

Dependence of a planet’s chaotic zone on particle eccentricity: the shape of debris disc inner edges

Mustill

Wyatt

2011

Monthly Notices of the Royal Astronomical Society

111

110

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The orbit of a planet is surrounded by a chaotic zone wherein nearby particles’ orbits are chaotic and unstable. It was shown by Wisdom that the chaos is driven by the overlapping of mean motion resonances which occurs within a distance (δa/a)chaos≈ 1.3μ2/7 of the planet’s orbit. However, the width of mean motion resonances grows with the particles’ eccentricity, which will increase the width of the chaotic zone at higher eccentricities. Here we investigate the width of the chaotic zone using the iterated encounter map and N‐body integrations. We find that the classical prescription of Wisdom works well for particles on low‐eccentricity orbits. However, above a critical eccentricity, dependent upon the mass of the planet, the width of the chaotic zone increases with eccentricity. An extension of Wisdom’s analytical arguments then shows that, above the critical eccentricity, the chaotic zone width is given by (δa/a)chaos≈ 1.8e1/5μ1/5, which agrees well with the encounter map results. The critical eccentricity is given by ecrit≈ 0.21μ3/7. This extended chaotic zone results in a larger cleared region when a planet sculpts the inner edge of a debris disc composed of eccentric planetesimals. Hence, the planet mass estimated from the classical chaotic zone may be erroneous. We apply this result to the HR 8799 system, showing that the mass of HR 8799 b inferred from the truncation of the disc may vary by up to 50 per cent depending on the disc particles’ eccentricities. With a disc edge at 90 au, the necessary mass of planet b to cause the truncation is 8–10 Jovian masses if the disc particles have low eccentricities (≲0.02), but only 4–8 Jovian masses if the disc particles have higher eccentricities. Our result also has implications for the ability of a planet to feed material into an inner system, a process which may explain metal pollution in white dwarf atmospheres.

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Section: Discussionmentioning

confidence: 99%

Dependence of a planet’s chaotic zone on particle eccentricity: the shape of debris disc inner edges

Mustill

Wyatt

2011

Monthly Notices of the Royal Astronomical Society

111

110

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“…Therefore, assuming reasonable values for b s , b g and q 3 we can find an analytic expression for the size distribution at different radii (e.g., Löhne et al 2008). Moreover, assuming an initial surface density or mass distribution in the disc, we can derive an expression for the fractional luminosity as a function of radius, as shown by Shannon & Wu (2011)…”

Section: Steady State Collisionally Evolved Disc Modelmentioning

confidence: 99%

ALMA observations of the multiplanet system 61 Vir: what lies outside super-Earth systems?

Marino

Wyatt

Kennedy

et al. 2017

Monthly Notices of the Royal Astronomical Society

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A decade of surveys has hinted at a possible higher occurrence rate of debris discs in systems hosting low mass planets. This could be due to common favourable forming conditions for rocky planets close in and planetesimals at large radii. In this paper we present the first resolved millimetre study of the debris disc in the 4.6 Gyr old multiplanet system 61 Vir, combining ALMA and JCMT data at 0.86 mm. We fit the data using a parametric disc model, finding that the disc of planetesimals extends from 30 AU to at least 150 AU, with a surface density distribution of millimetre sized grains with a power law slope of 0.1 +1.1 −0.8 . We also present a numerical collisional model that can predict the evolution of the surface density of millimetre grains for a given primordial disc, finding that it does not necessarily have the same radial profile as the total mass surface density (as previous studies suggested for the optical depth), with the former being flatter. Finally, we find that if the planetesimal disc was stirred at 150 AU by an additional unseen planet, that planet should be more massive than 10 M ⊕ and lie between 10-20 AU. Lower planet masses and semi-major axes down to 4 AU are possible for eccentricities 0.1.

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“…Even greater interest is added by the possibility that the outer asteroid belt may have supplied part of the volatile inventory of the Earth (Morbidelli et al 2000). Additionally, active asteroids are a source of dust for the Zodiacal cloud, while unseen counterpart bodies may supply dust to the debris disks of other stars (e.g., Shannon & Wu 2011).…”

Section: Introductionmentioning

confidence: 99%

The Active Asteroids

Jewitt

2012

The Astronomical Journal

295

244

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Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass-losing asteroids (also called "main-belt comets") can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider 11 dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses, and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation, while in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2, but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is probably due to cracking or dehydration at extreme (∼1000 K) perihelion temperatures, perhaps aided by radiation pressure sweeping. For the other bodies, the mass-loss mechanisms remain unidentified, pending the acquisition of more and better data. While the active asteroid sample size remains small, the evidence for an astonishing diversity of mass-loss processes in these bodies is clear.

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Planetesimals in Debris Disks of Sun-Like Stars

Cited by 53 publications

References 75 publications

Dependence of a planet’s chaotic zone on particle eccentricity: the shape of debris disc inner edges

Dependence of a planet’s chaotic zone on particle eccentricity: the shape of debris disc inner edges

ALMA observations of the multiplanet system 61 Vir: what lies outside super-Earth systems?

The Active Asteroids

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