Planetesimal/Debris discs

Marino, Sebastián

doi:10.48550/arxiv.2202.03053

Cited by 11 publications

(10 citation statements)

References 101 publications

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“…From a 0 and the full width at half maximum of the radial profile, we find a fractional width (FWHM/a 0 ) of 0.52. Even though the almost edge-on inclination is not ideal to constrain the width of the disk, this is in good agreement with other disks observed with ALMA (median width of 0.74, Marino 2021Marino , 2022. When summing the total flux in the best-fit model for the ALMA observations, we derive a total flux of 23.4 ± 0.3 mJy, compatible with the value reported in Cataldi et al (2020, 22.0 ± 2 mJy).…”

Section: Disk Geometrysupporting

confidence: 88%

The halo around HD 32297: μm-sized cometary dust

Olofsson

Thébault

Kennedy

et al. 2022

A&A

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Context. The optical properties of the second generation dust that we observe in debris disks remain quite elusive, whether it is the absorption efficiencies at millimeter wavelengths or the (un)polarized phase function at near-infrared wavelengths. Thankfully, the same particles are experiencing forces that are size dependent (e.g., radiation pressure) and, with high angular resolution observations, we can take advantage of this natural spatial segregation. Aims. Observations at different wavelengths probe different ranges of sizes; millimeter observations trace the larger grains, while nearinfrared observations are sensitive to the other extreme of the size distribution. Consequently, there is a great synergy in combining both observational techniques to better constrain the optical properties of the particles. Methods. We present a new approach to simultaneously model observations from "Spectro-Polarimetric High Contrast Exoplanet REsearch" (SPHERE) and the "Atacama Large Millimeter Array" (ALMA) and apply it to the debris disk around HD 32297, putting the emphasis on the spatial distribution of the grains with different β values. This modeling approach requires few assumptions on the actual sizes of the particles and the interpretation can therefore be done a posteriori. Results. We find that the ALMA observations are best reproduced with a combination of small and large β values (0.03 and 0.42) while the SPHERE observations require several intervals of β values. We discuss the nature of the halo previously reported in ALMA observations, and hypothesize it could be caused by over-abundant µm-sized particles (the over-abundance being the consequence of their extended lifetime). We modeled the polarized phase function at near-infrared wavelengths, and fluffy aggregates larger than a few µm provide the best solution. Conclusions. Comparing our results with comets of the Solar System, we postulate that the particles released in the disk originate from rather pristine cometary bodies (to avoid compaction of the fluffy aggregates) and they are then set on highly eccentric orbits, which could explain the halo detected at long wavelengths.

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Section: Disk Geometrysupporting

confidence: 88%

The halo around HD 32297: μm-sized cometary dust

Olofsson

Thébault

Kennedy

et al. 2022

A&A

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“…Since the rings of 2M041240 have low optical depth (see Section 4.1), the rapid formation of large grains that have negligible contributions to millimeter fluxes serves as a plausible explanation. Given the similar radial scale to cold ExoKuiper belts in debris disks, these dust rings might also be progenitors of old debris rings sustained by the collision of planetesimals formed within these high-density regions (Marino 2022;Najita et al 2022). On the contrary, those bright disks with inner cavities that depart from the main population, especially those few around low-mass hosts (M * < 1 M e ) that drive the M * − L mm relation, might be outliers where grain growth was inhibited within pressure bumps, if somehow grains did not fragment efficiently inside the pressure bumps due to the dust properties (such as composition) or because bouncing stops the effective growth.…”

Section: Context With Other Disksmentioning

confidence: 99%

A Large Double-ring Disk Around the Taurus M Dwarf J04124068+2438157

Long

Ren

Wallack

et al. 2023

ApJ

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Planet formation imprints signatures on the physical structures of disks. In this paper, we present high-resolution (∼50 mas, 8 au) Atacama Large Millimeter/submillimeter Array observations of 1.3 mm dust continuum and CO line emission toward the disk around the M3.5 star 2MASS J04124068+2438157. The dust disk consists of only two narrow rings at radial distances of 0.″47 and 0.″78 (∼70 and 116 au), with Gaussian σ widths of 5.6 and 8.5 au, respectively. The width of the outer ring is smaller than the estimated pressure scale height by ∼25%, suggesting dust trapping in a radial pressure bump. The dust disk size, set by the location of the outermost ring, is significantly larger (by 3σ) than other disks with similar millimeter luminosity, which can be explained by an early formation of local pressure bump to stop radial drift of millimeter dust grains. After considering the disk’s physical structure and accretion properties, we prefer planet–disk interaction over dead zone or photoevaporation models to explain the observed dust disk morphology. We carry out high-contrast imaging at the L ′ band using Keck/NIRC2 to search for potential young planets, but do not identify any source above 5σ. Within the dust gap between the two rings, we reach a contrast level of ∼7 mag, constraining the possible planet below ∼2–4 M Jup. Analyses of the gap/ring properties suggest that an approximately Saturn-mass planet at ∼90 au is likely responsible for the formation of the outer ring, which can potentially be revealed with JWST.

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“…During the collisional cascade, high velocity collisions gradually grind down larger solids into smaller solids, which are ejected from the system by stellar radiation pressure (e.g., Wyatt 2008;Kobayashi & Löhne 2014;Matthews et al 2014;Kobayashi et al 2019;Marino 2022). In the standard kinetic model, the evolution time for the cascade is roughly equivalent to the time required for a collision between the two largest particles in the swarm, which depends on the distance from the central star, the radius r max of the largest solid involved in the cascade, and the mass in solids with radii  r r max (e.g., Wyatt & Dent 2002;Dominik & Decin 2003;Krivov et al 2008;Wyatt 2008;Kenyon & Bromley 2017;Krivov & Wyatt 2021).…”

Section: Predicted Ir Excesses and Observational Limitsmentioning

confidence: 99%

Takeout and Delivery: Erasing the Dusty Signature of Late-stage Terrestrial Planet Formation

Najita

Kenyon

2023

ApJ

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The formation of planets like Earth is expected to conclude with a series of late-stage giant impacts that generate warm dusty debris, the most anticipated visible signpost of terrestrial planet formation in progress. While there is now evidence that Earth-sized terrestrial planets orbit a significant fraction of solar-type stars, the anticipated dusty debris signature of their formation is rarely detected. Here we discuss several ways in which our current ideas about terrestrial planet formation imply transport mechanisms capable of erasing the anticipated debris signature. A tenuous gas disk may be regenerated via takeout (i.e., the liberation of planetary atmospheres in giant impacts) or delivery (i.e., by asteroids and comets flung into the terrestrial planet region) at a level sufficient to remove the warm debris. The powerful stellar wind from a young star can also act, its delivered wind momentum producing a drag that removes warm debris. If such processes are efficient, terrestrial planets may assemble inconspicuously, with little publicity and hoopla accompanying their birth. Alternatively, the rarity of warm excesses may imply that terrestrial planets typically form very early, emerging fully formed from the nebular phase without undergoing late-stage giant impacts. In either case, the observable signposts of terrestrial planet formation appear more challenging to detect than previously assumed. We discuss observational tests of these ideas.

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Planetesimal/Debris discs

Cited by 11 publications

References 101 publications

The halo around HD 32297: μm-sized cometary dust

The halo around HD 32297: μm-sized cometary dust

A Large Double-ring Disk Around the Taurus M Dwarf J04124068+2438157

Takeout and Delivery: Erasing the Dusty Signature of Late-stage Terrestrial Planet Formation

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