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Esposito, Richard; Aubert, Dominique; Gautier, Pascal; Santerre, Bernard

doi:10.1016/b978-2-294-76513-1.00013-1

Cited by 12 publications

(21 citation statements)

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“…With gas drag (applied using A = 0.04 s/km and η kick = 10 2 ), many dust grain apsides are forced into much better alignment (Figure 4, middle); a "kink" appears in the wingtips, in addition to a "double wing". These features, which resemble those observed in HD 61005 (e.g., Esposito et al 2016) and HD 32297 (e.g., Schneider et al 2014), manifest whether we employ a Henyey-Greenstein SPF with g = 0.5 (middle panel) or a Hedman & Stark (2015) SPF derived from Saturn's rings (right panel). However, using the Hedman-Stark SPF generates a bulbous top reminiscent of those seen in HD 32297 (see panels B and C of Figure 19 of Schneider et al 2014) and HD 61005 (see Figure 21 of Schneider et al 2014); the "bulb" traces dust at the apastra of attractor orbits (Figure 4, right) made visible by strong forward scattering.…”

Section: Man and Starksupporting

confidence: 60%

“…In HD 61005 (the eponymous "Moth"; Hines et al 2007;Maness et al 2009;Ricarte et al 2013), the wingtips are canted by ∼23 • (Buenzli et al 2010;Esposito et al 2016). Such a large, order-unity "kink" from the horizontal (Esposito et al 2016 refer to this feature as an "elbow") cannot be reproduced if dust grain orbits are apsidally misaligned; the resultant density distribution is too axially symmetric and the isophotes too rounded (LC16, their Figure 6). The second feature that hinges on apsidal alignment is the "double wing"-a secondary band of light which is offset from the star and nearly parallel to the primary band (LC16, their Figure 9).…”

Section: Introductionmentioning

confidence: 99%

“…The secondary wing traces overdensities that are peculiar to perfectly apsidally aligned orbits whose apastra span a large range (LC16, their Figure 7; we recapitulate their explanation in §3 of our paper). The debris disk HD 32297 is a double-winged moth (see Figures 18 and 19 of Schneider et al 2014) as is HD 61005 (see Figure 7 of Schneider et al 2014;Esposito et al 2016 refer to the multiple radial extensions as "spurs").…”

Section: Introductionmentioning

confidence: 99%

“…Dust particles are not apsidally aligned when launched from an apse-aligned ring of parent bodies; stellar radiation pressure disperses dust grain longitudes of periastra so that they span the full gamut between 0 and 2π (e.g., equation 10 of LC16). The apsidally aligned configurations modeled by LC16 were assumed without justification; they resulted from demanding that dust-producing collisions between parent bodies occur strictly at periastron of the parent ring (their "periapse only" scenario; see also Esposito et al 2016 who made the same assumption). But restricting collisions to periastron only is unphysical; relative velocities and densities of parent bodies can vary only smoothly and quasi-sinusoidally with orbital phase, with collisions happening everywhere.…”

Section: Introductionmentioning

confidence: 99%

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Sculpting Eccentric Debris Disks with Eccentric Gas Rings

Lin

Chiang

2019

ApJ

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Many debris disks seen in scattered light have shapes that imply their dust grains trace highly eccentric, apsidally aligned orbits. Apsidal alignment is surprising, especially for dust. Even when born from an apse-aligned ring of parent bodies, dust grains have their periastra dispersed in all directions by stellar radiation pressure. The periastra cannot be re-oriented by planets within the short dust lifetimes at the bottom of the collisional cascade. We propose that what re-aligns dust orbits is drag exerted by second-generation gas. Gas is largely immune to radiation pressure, and when released by photodesorption or collisions within an eccentric ring of parent bodies should occupy a similarly eccentric, apse-aligned ring. Dust grains launched onto misaligned orbits cross the eccentric gas ring supersonically and can become dragged into alignment within collisional lifetimes. The resultant dust configurations, viewed nearly but not exactly edge-on, with periastra pointing away from the observer, appear moth-like, with kinked wings and even doubled pairs of wings, explaining otherwise mysterious features in HD 61005 ("The Moth") and HD 32297, including their central bulbs when we account for strong forward scattering from irregularly shaped particles. Around these systems we predict gas at Kuiper-belt-like distances to move on highly elliptical streamlines that owe their elongation, ultimately, to highly eccentric planets. Unresolved issues and an alternative explanation for apsidal alignment are outlined.

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Section: Man and Starksupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sculpting Eccentric Debris Disks with Eccentric Gas Rings

Lin

Chiang

2019

ApJ

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“…Lee & Chiang (2016) presented numerical simulations that can explain a variety of morphologies of debris disks. Their code, which can account for the effect of stellar radiation pressure, was used by Esposito et al (2016) to model GPI observations of the debris disk around HD 61005. Overall, thanks to the exquisite spatial resolution provided by this new generation of instruments, we are able to perform in-depth studies of young and bright debris disks, trying to constrain the collisional activity responsible for the production of small dust grains.…”

Section: Introductionmentioning

confidence: 99%

Dust production in the debris disk around HR 4796 A

Olofsson

Milli

Thébault

et al. 2019

A&A

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Context. Debris disks are the natural by-products of the planet formation process. Scattered or polarized light observations are mostly sensitive to small dust grains that are released from the grinding down of bigger planetesimals. Aims. High angular resolution observations at optical wavelengths can provide key constraints on the radial and azimuthal distribution of the small dust grains. These constraints can help us better understand where most of the dust grains are released upon collisions. Methods. We present SPHERE/ZIMPOL observations of the debris disk around HR 4796 A, and model the radial profiles along several azimuthal angles of the disk with a code that accounts for the effect of stellar radiation pressure. This enables us to derive an appropriate description for the radial and azimuthal distribution of the small dust grains. Results. Even though we only model the radial profiles along (or close to) the semi-major axis of the disk, our best-fit model is not only in good agreement with our observations but also with previously published datasets (from near-IR to sub-mm wavelengths). We find that the reference radius is located at 76.4 ± 0.4 au, and the disk has an eccentricity of 0.076 +0.016 −0.010 , with the pericenter located on the front side of the disk (north of the star). We find that small dust grains must be preferentially released near the pericenter to explain the observed brightness asymmetry. Conclusions. Even though parent bodies spend more time near the apocenter, the brightness asymmetry implies that collisions happen more frequently near the pericenter of the disk. Our model can successfully reproduce the shape of the outer edge of the disk, without having to invoke an outer planet shepherding the debris disk. With a simple treatment of the effect of the radiation pressure, we conclude that the parent planetesimals are located in a narrow ring of about 3.6 au in width.

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Quantum Features and Signatures of Quantum Thermal Machines

Levy

Gelbwaser-Klimovsky

2018

Fundamental Theories of Physics

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The aim of this book chapter is to indicate how quantum phenomena are affecting the operation of microscopic thermal machines, such as engines and refrigerators. As converting heat to work is one of the fundamental concerns in thermodynamics, the platform of quantum-thermal machines sheds light on thermodynamics in the quantum regime. This chapter focuses on the basic features of quantum mechanics, such as energy quantization, the uncertainty principle, quantum coherence and correlations, and their manifestation in microscopic thermal devices. In addition to indicating the peculiar behaviors of thermal-machines due to their non-classical features, we present quantum-thermodynamic signatures of these machines. Any violation of the classical bounds on thermodynamic measurements of these machines is a sufficient condition to conclude that quantum effects are present in the operation of that thermal machine. Experimental setups demonstrating some of the results are also presented. *

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Cited by 12 publications

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Sculpting Eccentric Debris Disks with Eccentric Gas Rings

Sculpting Eccentric Debris Disks with Eccentric Gas Rings

Dust production in the debris disk around HR 4796 A

Quantum Features and Signatures of Quantum Thermal Machines

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