Wavy size distributions for collisional systems with a small-size cutoff

Bagatín, Adriano Campo; Cellino, A.; Davis, Donald R.; Farinella, P.; Paolicchi, Paolo

doi:10.1016/0032-0633(94)90008-6

Cited by 140 publications

(120 citation statements)

References 21 publications

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“…This might influence modeling of disk's spectral properties and disk mass estimates. The pattern is well understood (Campo Bagatin et al 1994) as the result of the lower size cut-off produced by the blowout due to radiation pressure and was obtained by other models (Thébault et al 2003), too. The reported peak at a grain size twice as large as the smallest bound grains is found as well as the lack of grains 20 to 100 times as large.…”

Section: Discussionsupporting

confidence: 59%

“…Due to this lack of possible impactors, grains slightly above this size limit are overabundant, thereby reducing the number of grains of the next larger population, and so on. This dependence produces a well-known wavy pattern in the size or mass distribution (e.g., Campo Bagatin et al 1994;Durda & Dermott 1997;Thébault et al 2003), whose "wavelength" depends on the ratio of the average impact energy available and the impact energy Q * D needed to disrupt a given target. The first is controled by impact velocities, which depend on the disk's layout.…”

Section: Resultsmentioning

confidence: 99%

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Dust distributions in debris disks: effects of gravity, radiation pressure and collisions

Krivov¹,

Löhne²,

Sremčević

2006

A&A

184

308

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We model a typical debris disk, treated as an idealized ensemble of dust particles, exposed to stellar gravity and direct radiation pressure and experiencing fragmenting collisions. Applying the kinetic method of statistical physics, written in orbital elements, we calculate size and spatial distibutions expected in a steady-state disk, investigate timescales needed to reach the steady state, and calculate mass loss rates. Particular numerical examples are given for the debris disk around Vega. The disk should comprise a population of larger grains in bound orbits and a population of smaller particles in hyperbolic orbits. The cross section area is dominated by the smallest grains that still can stay in bound orbits, for Vega about 10 µm in radius. The size distribution is wavy, implying secondary peaks in the size distribution at larger sizes. The radial profile of the pole-on surface density or the optical depth in the steady-state disk has a power-law index between about −1 and −2. It cannot be much steeper even if dust production is confined to a narrow planetesimal belt, because collisional grinding produces smaller and smaller grains, and radiation pressure pumps up their orbital eccentricities and spreads them outward, which flattens the radial profile. The timescales to reach a steady state depend on grain sizes and distance from the star. For Vega, they are about 1 Myr for grains up to some hundred µm at 100 AU. The total mass of the Vega disk needed to produce the observed amount of micron and submillimeter-sized dust does not exceed several earth masses for an upper size limit of parent bodies of about 1 km. The collisional depletion of the disk occurs on Gyr timescales.

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Section: Discussionsupporting

confidence: 59%

Section: Resultsmentioning

confidence: 99%

Dust distributions in debris disks: effects of gravity, radiation pressure and collisions

Krivov¹,

Löhne²,

Sremčević

2006

A&A

184

308

View full text Add to dashboard Cite

show abstract

“…However, notable ripples appear near physical breaks or cutoffs. Waves in the size distribution are induced for asteroids by the transition from strength to self-gravity (Durda & Dermott 1997) and for grains above the blowout limit by the radiation pressure cutoff (Campo Bagatin et al 1994). At this lower size end, barely bound grains become overabundant because of a lack of smaller projectiles.…”

Section: Effects Of Collisionsmentioning

confidence: 99%

Collisions and drag in debris discs with eccentric parent belts

Löhne

Krivov

Kirchschlager

et al. 2017

A&A

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Context. High-resolution images of circumstellar debris discs reveal off-centred rings that indicate past or ongoing perturbation, possibly caused by secular gravitational interaction with unseen stellar or substellar companions. The purely dynamical aspects of this departure from radial symmetry are well understood. However, the observed dust is subject to additional forces and effects, most notably collisions and drag. Aims. To complement the studies of dynamics, we therefore aim to understand how new asymmetries are created by the addition of collisional evolution and drag forces, and existing ones strengthened or overridden. Methods. We augmented our existing numerical code "Analysis of Collisional Evolution" (ACE) by an azimuthal dimension, the longitude of periapse. A set of fiducial discs with global eccentricities ranging from 0 to 0.4 is evolved over giga-year timescales. Size distribution and spatial variation of dust are analysed and interpreted. The basic impact of belt eccentricity on spectral energy distributions (SEDs) and images is discussed. Results. We find features imposed on characteristic timescales. First, radiation pressure defines size cutoffs that differ between periapse and apoapse, resulting in an asymmetric halo. The differences in size distribution make the observable asymmetry of the halo depend on wavelength. Second, collisional equilibrium prefers smaller grains on the apastron side of the parent belt, reducing the effect of pericentre glow and the overall asymmetry. Third, Poynting-Robertson drag fills the region interior to an eccentric belt such that the apastron side is more tenuous. Interpretation and prediction of the appearance in scattered light is problematic when spatial and size distribution are coupled.

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“…Particles with β > 0.5 are depleted by about three orders of magnitude in terms of collective cross-section. Superimposed on the power law is a well-known wave pattern related to the discontinuity in the size distribution at the blowout size (see, e.g., Campo Bagatin et al 1994;Durda & Dermott 1997;Gáspár et al 2012). The first bump (i.e., the one at β ≈ 0.5) in the size distribution at r = 30 AU does not extend far above the powerlaw prediction.…”

Section: Size Distributionmentioning

confidence: 99%

Near-infrared emission from sublimating dust in collisionally active debris disks

Lieshout

Dominik

Kama

et al. 2014

A&A

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Context. Hot exozodiacal dust is thought to be responsible for excess near-infrared (NIR) emission emanating from the innermost parts of some debris disks. The origin of this dust, however, is still a matter of debate. Aims. We test whether hot exozodiacal dust can be supplied from an exterior parent belt by Poynting-Robertson (P-R) drag, paying special attention to the pile-up of dust that occurs owing to the interplay of P-R drag and dust sublimation. Specifically, we investigate whether pile-ups still occur when collisions are taken into account, and if they can explain the observed NIR excess. Methods. We computed the steady-state distribution of dust in the inner disk by solving the continuity equation. First, we derived an analytical solution under a number of simplifying assumptions. Second, we developed a numerical debris disk model that for the first time treats the complex interaction of collisions, P-R drag, and sublimation in a self-consistent way. From the resulting dust distributions, we generated thermal emission spectra and compare these to observed excess NIR fluxes. Results. We confirm that P-R drag always supplies a small amount of dust to the sublimation zone, but find that a fully consistent treatment yields a maximum amount of dust that is about 7 times lower than that given by analytical estimates. The NIR excess due to this material is much less ( < ∼ 10 −3 for A-type stars with parent belts at > ∼ 1 AU) than the values derived from interferometric observations (∼10 −2 ). Pile-up of dust still occurs when collisions are considered, but its effect on the NIR flux is insignificant. Finally, the cross-section in the innermost regions is clearly dominated by barely bound grains.

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Wavy size distributions for collisional systems with a small-size cutoff

Cited by 140 publications

References 21 publications

Dust distributions in debris disks: effects of gravity, radiation pressure and collisions

Dust distributions in debris disks: effects of gravity, radiation pressure and collisions

Collisions and drag in debris discs with eccentric parent belts

Near-infrared emission from sublimating dust in collisionally active debris disks

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