Accretion of eroding pebbles and planetesimals in planetary envelopes

Demirci, Tunahan; Wurm, Gerhard

doi:10.1051/0004-6361/202038690

Cited by 6 publications

(4 citation statements)

References 30 publications

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“…However, the possibility that planetary bodies can grow to the size of Ceres or beyond by pebble accretion (Lambrechts & Johansen 2012;Bitsch et al 2015) provides a model by which the CV, CM, and CK parent bodies could have acquired their distinctive gravity plus volatility chemical topography during construction. Incoming pebbles that were partially or wholly ablated by wind erosion (Demirci & Wurm 2020), vaporized during their collision with the protoplanet, or vaporized by the impact of subsequent impactors would deliver material to the parent body's gravitational well at or near the planetary surface. The combined effects of volatility and Jeans escape would then be poised to influence the separation of low-mass volatile elements from elements with higher mass and or lower volatility.…”

Section: Chemical Topographic Evidence For Pebble Accretion?mentioning

confidence: 99%

Large Carbonaceous Chondrite Parent Bodies Favored by Abundance–Volatility Modeling: A Possible Chemical Signature of Pebble Accretion

Boyce,

McCubbin,

Lunning

et al. 2024

Planet. Sci. J.

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Primitive meteorite groups such as the Vigarano, Mighei, and Karoonda carbonaceous chondrites have enigmatic patterns of elemental abundances, with moderately volatile elements—those that transition from vapor to condensate between ∼400 and ∼900 K—defining plateaus of subequal abundances despite a wide range in volatility. In detail, each group defines a plateau with distinctive nonmonotonic “chemical fingerprints” that have been attributed to combinations of mixing, vaporization/condensation, and fluid-mediated metasomatism—but the extent to which these processes can reproduce the observed variability has not been quantified. Starting with primitive Ivuna chondrite, a two-stage, two-component equilibrium condensation–vaporization model—with gravity implemented as Jeans escape—can explain large-scale plateaus in these chondrite groups, as well as more complex, nonmonotonic small-scale variations. For all three chondritic meteorite groups, models favor earlier high-temperature fractionation under low-gravity conditions followed by a low-temperature fractionation event that took place on a protoplanet at least as large as Ceres. The second fractionation event may represent the fractionation of incoming materials to the planetesimal during protracted pebble accretion. Models with only thermally driven volatile loss, gravity, and mixing can explain more than 80% of the observed compositional variability in these meteorite groups. In our five-parameter model, using only five randomly selected elements yields uselessly large ranges of planet sizes and temperatures, ranges that converge with increasing numbers of elements. These results suggest that even simple models are prone to generating inaccurate conclusions when constrained by too few observations, a fault likely held by more complex models as well.

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Section: Chemical Topographic Evidence For Pebble Accretion?mentioning

confidence: 99%

Large Carbonaceous Chondrite Parent Bodies Favored by Abundance–Volatility Modeling: A Possible Chemical Signature of Pebble Accretion

Boyce,

McCubbin,

Lunning

et al. 2024

Planet. Sci. J.

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“…Finally, a further consequence is the erosion of planetesimals with respect to pebble accretion somewhat later in the evolution toward planets (Demirci & Wurm 2020). Even if planetesimals in the outer region are stable during their formation, when they later interact with a forming giant planet or planet with an atmosphere, the increased gas density will again allow a disassembly of the planetesimals.…”

Section: Erosion In Protoplanetary Disksmentioning

confidence: 99%

“…Even if planetesimals in the outer region are stable during their formation, when they later interact with a forming giant planet or planet with an atmosphere, the increased gas density will again allow a disassembly of the planetesimals. This has a large impact on the mass balance of accretion (Demirci & Wurm 2020).…”

Section: Erosion In Protoplanetary Disksmentioning

confidence: 99%

“…The thickness of the laminar boundary layer around a planetesimal is not well defined, and different approaches were used to estimate it (Demirci & Wurm 2020;Cedenblad et al 2021;Schlichting & Gersten 2006). We used the following two boundary-layer-approximations for the calculation of τ w : Schlichting & Gersten (2006).…”

Section: Forbidden Orbits For Planetesimalsmentioning

confidence: 99%

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Forbidden planetesimals

Schönau

Teiser

Demirci

et al. 2023

A&A

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Planetesimals are born fragile and are subject to destruction by wind erosion as they move through the gas of a protoplanetary disk. In microgravity experiments, we determined the shear stress necessary for erosion of a surface consisting of 1 mm dust pebbles down to 1 Pa ambient pressure. This is directly applicable to protoplanetary disks. Even pebble pile planetesimals with low eccentricities of 0.1 cannot survive inside of 1 au in a minimum-mass solar nebula, and safe zones for planetesimals with higher eccentricities are located even farther out.

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