Multistage Core Formation in Planetesimals Revealed by Numerical Modeling and Hf‐W Chronometry of Iron Meteorites

Neumann, Wladimir; Kruijer, T. S.; Breuer, D.; Kleine, T.

doi:10.1002/2017je005411

Cited by 13 publications

(16 citation statements)

References 69 publications

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“…Our results suggest that ordinary chondrites in reality most likely sample differentiated, partially differentiated and perhaps even undifferentiated parent bodies 42,43 .…”

mentioning

confidence: 75%

“…Ordinary chondrites are usually linked to undifferentiated parent bodies 41 , which should have accreted after most 26 Al has been extinct (e.g. >2 Myr) or thought to be the undifferentiated shells of (partially) differentiated planetesimals 42,43 . Chondrule ages in ordinary chondrites suggest that their parent bodies accreted 2-3Myr after CAIs 2 .…”

mentioning

confidence: 99%

“…Chondrule ages in ordinary chondrites suggest that their parent bodies accreted 2-3Myr after CAIs 2 . Chondrules in ordinary chondrites may sample material from the outermost chondritic layers of early formed planetesimals 44 , with onion-shell structures 42,43 .…”

mentioning

confidence: 99%

“…These layers may be hot and molten 45 but undifferentiated 43 and get excavated by impacts generating chondrules 46 . Jupiter's formation is also expected to trigger the formation of chondrules in the disk 47 , if it interacts with a population of planetesimals existing in the belt (e.g.…”

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confidence: 99%

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Planetesimal rings as the cause of the Solar System's planetary architecture

Izidoro,

Dasgupta,

Raymond

et al. 2021

Preprint

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Astronomical observations reveal that protoplanetary disks around young stars commonly have ring-and gap-like structures in their dust distributions. These features are associated with pressure bumps trapping dust particles at specific locations, which simulations show are ideal sites for planetesimal formation. Here we show that our Solar System may have formed from rings of planetesimals -created by pressure bumps -rather than a continuous disk. We model the gaseous disk phase assuming the existence of pressure bumps near the silicate sublimation line (at T ∼1400 K), water snowline (at T ∼170 K), and CO-snowline (at T ∼30 K). Our simulations show that dust piles up at the bumps and forms up to three rings of planetesimals: a narrow ring near 1 au, a wide ring between ∼3-4 au and ∼10-20 au, and a distant ring between ∼20 au and ∼45 au. We use a series of simulations to follow the evolution of the innermost ring and show how it can explain the orbital structure of the inner Solar System and provides a framework to explain the origins of isotopic signatures of Earth, Mars and different classes of meteorites. The central ring contains enough mass to explain

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“…Our results suggest that ordinary chondrites in reality most likely sample differentiated, partially differentiated and perhaps even undifferentiated parent bodies 42,43 .…”

mentioning

confidence: 75%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Planetesimal rings as the cause of the Solar System's planetary architecture

Izidoro,

Dasgupta,

Raymond

et al. 2021

Preprint

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“…Impacts can incite degassing by formation of limited surficial magma ponds (65) or by postimpact excavation of the interior (66,67). Partial degassing is also expected in the multistage planetesimal core formation models proposed by Neumann et al (68). In the fourth case (4C), degassing of the silicate portion of the planetesimal occurs owing to formation of an uncovered magma ocean (13).…”

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confidence: 94%

Early volatile depletion on planetesimals inferred from C–S systematics of iron meteorite parent bodies

Hirschmann

Bergin

Blake

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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During the formation of terrestrial planets, volatile loss may occur through nebular processing, planetesimal differentiation, and planetary accretion. We investigate iron meteorites as an archive of volatile loss during planetesimal processing. The carbon contents of the parent bodies of magmatic iron meteorites are reconstructed by thermodynamic modeling. Calculated solid/molten alloy partitioning of C increases greatly with liquid S concentration, and inferred parent body C concentrations range from 0.0004 to 0.11 wt%. Parent bodies fall into two compositional clusters characterized by cores with medium and low C/S. Both of these require significant planetesimal degassing, as metamorphic devolatilization on chondrite-like precursors is insufficient to account for their C depletions. Planetesimal core formation models, ranging from closed-system extraction to degassing of a wholly molten body, show that significant open-system silicate melting and volatile loss are required to match medium and low C/S parent body core compositions. Greater depletion in C relative to S is the hallmark of silicate degassing, indicating that parent body core compositions record processes that affect composite silicate/iron planetesimals. Degassing of bare cores stripped of their silicate mantles would deplete S with negligible C loss and could not account for inferred parent body core compositions. Devolatilization during small-body differentiation is thus a key process in shaping the volatile inventory of terrestrial planets derived from planetesimals and planetary embryos.

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