Particle size distributions in chondritic meteorites: Evidence for pre-planetesimal histories

Simon, Justin I.; Cuzzi, Jeffrey N.; McCain, K. A.; Cato, M. J.; Christoffersen, P. A.; Fisher, Kent R.; Srinivasan, Poorna; Tait, Alastair W.; Olson, Daniel M.; Scargle, Jeffrey D.

doi:10.1016/j.epsl.2018.04.021

Cited by 47 publications

(49 citation statements)

References 65 publications

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“…There are many studies of the accretion process of chondrules, and some of these studies focus on the effect of fine dust grains accreted onto chondrules. It is known that some of the chondrules in ordinary and carbonaceous chondrites are rimmed by fine dust grains (∼ 15% for chondrules in Allende CV3 chondrite, Simon et al 2018). Theoretical studies have also revealed that free-floating chondrules in a protoplanetary disk can obtain porous dust layers (e.g., Xiang et al 2019), which help dust-rimmed chondrules stick together when they collide (Beitz et al 2012;Gunkelmann et al 2017).…”

Section: Accretion Of Chondrulesmentioning

confidence: 99%

Compound Chondrule Formation in Optically Thin Shock Waves

Arakawa

Nakamoto

2019

ApJ

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Shock-wave heating within the solar nebula is one of the leading candidates for the source of chondruleforming events. Here, we examine the possibility of compound chondrule formation via optically thin shock waves. Several features of compound chondrules indicate that compound chondrules are formed via the collisions of supercooled precursors. We evaluate whether compound chondrules can be formed via the collision of supercooled chondrule precursors in the framework of the shock-wave heating model by using semi-analytical methods and discuss whether most of the crystallized chondrules can avoid destruction upon collision in the post-shock region. We find that chondrule precursors immediately turn into supercooled droplets when the shock waves are optically thin and they can maintain supercooling until the condensation of evaporated fine dust grains. Owing to the large viscosity of supercooled melts, supercooled chondrule precursors can survive high-speed collisions on the order of 1 km s −1 when the temperature is below ∼ 1400 K. From the perspective of the survivability of crystallized chondrules, shock waves with a spatial scale of ∼ 10 4 km may be potent candidates for the chondrule formation mechanism. Based on our results from one-dimensional calculations, a fraction of compound chondrules can be reproduced when the chondrule-to-gas mass ratio in the pre-shock region is ∼ 2 × 10 −3 , which is approximately half of the solar metallicity.

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Section: Accretion Of Chondrulesmentioning

confidence: 99%

Compound Chondrule Formation in Optically Thin Shock Waves

Arakawa

Nakamoto

2019

ApJ

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“…The anomalously small CO and CM chondrules still require an explanation, but our model clearly is consistent with particle concentration by turbulence. This strongly suggests that aggregates of chondrules can form as described by Simon et al (2018), and that these aggregates of particles are what are concentrated by streaming instability. This further provides strong support for the model assumption that chondrites represent snapshots in time of the solar nebula.…”

Section: Aerodynamic Sorting Into Planetesimalsmentioning

confidence: 81%

“…A challenge for the streaming instability model is that the particles that are abundant in the solar nebula-chondrules and CAIs-are typically millimeter-sized and are characterized by Ω t stop < 10 −3 , whereas the particles that are concentrated by streaming instability must be meter-sized to have Ω t stop ∼ 0.3. Cuzzi et al (2017) and Simon et al (2018) suggest that turbulent concentration first concentrates chondrules and small objects into aggregates 10 cm in size or larger; these aggregates then are concentrated by streaming instability. Two neighboring lithologies in the ordinary chondrite NWA 5717 show strong evidence of being two such aggregates that were assembled into that parent body (Simon et al 2018).…”

Section: Carbonaceous Chondritesmentioning

confidence: 99%

The Effect of Jupiter's Formation on the Distribution of Refractory Elements and Inclusions in Meteorites

Desch

Kalyaan

Alexander

2018

ApJS

208

254

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We present a comprehensive evolutionary model of the Sun's protoplanetary disk, constructed to resolve the "CAI Storage" problem of meteoritics. We predict the abundances of calcium-rich, aluminum-rich inclusions (CAIs) and refractory lithophile elements under the central assumption that Jupiter's ∼ 30 M ⊕ core forms at about 3 AU at around 0.6 Myr and opened a gap CAIs are trapped in the pressure maximum beyond Jupiter; carbonaceous chondrites formed there. Inside Jupiter's orbit, CAIs were depleted by aerodynamic drag; ordinary and enstatite chondrites formed there. For 16 chondrites and achondrites, we review meteoritic data on their CAI and refractory abundances and their times of formation, constrained by radiometric dating and thermal models. We predict their formation locations, finding excellent consistency with other location information (water content, asteroid spectra and parent bodies). We predict the size of particle concentrated by turbulence for each chondrite, finding excellent matches to each chondrites's mean chondrule diameter. These consistencies imply meteorite parent bodies assembled quickly from local materials concentrated by turbulence, and usually did not migrate far. We predict CI chondrites are depleted in refractory lithophile elements relative to the Sun, by about 12% (0.06 dex). We constrain the variation of turbulence parameter α in the disk, and find a limited role for magnetorotational instability, favoring hydrodynamical instabilities in the outer disk, plus magnetic disk winds in the inner disk. Between 3 and 4 Myr at least, gas persisted outside Jupiter but was depleted inside it, and the solar nebula was a transition disk.

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“…The values of C are given for "common" probability levels of F p (> C) = 50% and 30%, and a "rare" probability level of F p (> C) = 1%. As an example, chondrule aggregates of between 1.5 and 2.6cm radius are apparently seen in the primitive ordinary chondrite NWA5717 (Simon et al 2018). According to Table 3, "particles" of 2.6 cm radius, whether aggregates of chondrules or of chondrule precursors, are commonly found in 500 − 1000 km size regions with average concentrations of 50−140.…”

Section: Comments On General Trendsmentioning

confidence: 99%

“…However, actual observations are telling us that the current models, based on laboratory sticking measurements, may be missing something. Simon et al (2018) have analyzed a very primitive ordinary chondrite, which has the unusual property of containing two visually distinct (dark and light) "lithologies" which on closer examination are, apparently, aggregates of chondrules formed in two very different regions, as reflected in their very different chemical and isotopic compositions (and slightly different particle sizes, even). Somehow, nature is making several-cm-diameter aggregates of chondrules even if our models are not yet doing so (cf.…”

Section: Comments On General Trendsmentioning

confidence: 99%

Cascade Model for Planetesimal Formation by Turbulent Clustering

Hartlep

Cuzzi

2020

ApJ

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We use a newly developed cascade model of turbulent concentration of particles in protoplanetary nebulae to calculate several properties of interest to the formation of primitive planetesimals and to the meteorite record. The model follows, and corrects, calculations of the primary planetesimal Initial Mass Function (IMF) by Cuzzi et al. (2010), in which an incorrect cascade model was used. Here we use the model of Hartlep et al. ( 2017), which has been validated against several published numerical simulations of particle concentration in turbulence. We find that, for a range of nebula and particle properties, planetesimals may be "born big", formed as sandpiles with diameters in the 10 − 100 km range, directly from freely floating particles. The IMFs have a modal nature, with a well-defined peak rather than a powerlaw size dependence. Predictions for the inner and outer nebula behave similarly in these regards, and observations of inner and outer nebula primitive bodies support such modal IMFs. Also, we present predictions of local particle concentrations on several lengthscales in which particles "commonly" find themselves, which have significance for meteoritical observations of the redox state and isotopic fractionation in regions of chondrule formation. An important difference between these results, and those of Cuzzi et al. (2010), is that particle growth-by-sticking must proceed to at least the 1−few cm radius range for the IMF and meteoritical properties to be most plausibly satisfied. That is, as far as the inner nebula goes, the predominant "particles" must be aggregates of chondrules (or chondrule-size precursors) rather than individual chondrules themselves.

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Particle size distributions in chondritic meteorites: Evidence for pre-planetesimal histories

Cited by 47 publications

References 65 publications

Compound Chondrule Formation in Optically Thin Shock Waves

Compound Chondrule Formation in Optically Thin Shock Waves

The Effect of Jupiter's Formation on the Distribution of Refractory Elements and Inclusions in Meteorites

Cascade Model for Planetesimal Formation by Turbulent Clustering

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