Sulfur chemistry with time-varying oxygen abundance during Solar System formation

Pasek, Matthew A.; Milsom, John A.; Ciesla, F. J.; Лауретта, Д. С.; Sharp, Catherine; Lunine, Jonathan I.

doi:10.1016/j.icarus.2004.10.012

Cited by 97 publications

(112 citation statements)

References 54 publications

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“…Models for the formation of the enstatite chondrites suggest that removal of more than 50% of the water in the nebula had to have taken place in order for the observed minerals to become stable (Hutson and Ruzicka, 2000;Pasek et al, 2005). Such a situation is realized in the model runs presented here, but after millions of years of evolution.…”

Section: Inner Nebula and Chondritic Parent Bodiesmentioning

confidence: 73%

The evolution of the water distribution in a viscous protoplanetary disk

Ciesla

Cuzzi

2006

Icarus

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312

354

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Astronomical observations have shown that protoplanetary disks are dynamic objects through which mass is transported and accreted by the central star. This transport causes the disks to decrease in mass and cool over time, and such evolution is expected to have occurred in our own solar nebula. Age dating of meteorite constituents shows that their creation, evolution, and accumulation occupied several Myr, and over this time disk properties would evolve significantly. Moreover, on this timescale, solid particles decouple from the gas in the disk and their evolution follows a different path. It is in this context that we must understand how our own solar nebula evolved and what effects this evolution had on the primitive materials contained within it. Here we present a model which tracks how the distribution of water changes in an evolving disk as the water-bearing species experience condensation, accretion, transport, collisional destruction, and vaporization. Because solids are transported in a disk at different rates depending on their sizes, the motions will lead to water being concentrated in some regions of a disk and depleted in others. These enhancements and depletions are consistent with the conditions needed to explain some aspects of the chemistry of chondritic meteorites and formation of giant planets. The levels of concentration and depletion, as well as their locations, depend strongly on the combined effects of the gaseous disk evolution, the formation of rapidly migrating rubble, and the growth of immobile planetesimals. Understanding how these processes operate simultaneously is critical to developing our models for meteorite parent body formation in the solar system and giant planet formation throughout the galaxy. We present examples of evolution under a range of plausible assumptions and demonstrate how the chemical evolution of the inner region of a protoplanetary disk is intimately connected to the physical processes which occur in the outer regions.

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Section: Inner Nebula and Chondritic Parent Bodiesmentioning

confidence: 73%

The evolution of the water distribution in a viscous protoplanetary disk

Ciesla

Cuzzi

2006

Icarus

Self Cite

312

354

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“…Hydrogen sulfide, the most abundant sulfur-bearing gas in the early solar system, is suggested to have resided within the inner ∼2 AU of the young solar nebula (28,29), and near the surfaces of the disk, because temperatures exceeded ∼700 K, resulting in the evaporation of troilite. Ly-α radiation from the Sun would have been highest during the T-Tauri phase of solar history, which lasts ∼2 My for a star of solar mass (30).…”

Section: Resultsmentioning

confidence: 99%

“…However, mechanisms through which these isotope signatures were incorporated into protoplanets remain poorly understood. Due to the higher condensation temperatures of refractory sulfides, such as oldhamite (CaS) [(∼1,200 K) (28)], compared with silicates, their condensation likely occurred within a region optically clear to UV radiation from the young sun. However, the condensation temperature of troilite (∼700 K) is inferior to that of most silicates (28), making it likely that it condensed at higher optical depths.…”

Section: Resultsmentioning

confidence: 99%

Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets

Antonelli

Kim

Peters

et al. 2014

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

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Achondrite meteorites have anomalous enrichments in 33 S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying 33 S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the 33 S anomalies, or of the bulk solar system S-isotope composition. Here, we report wellresolved anomalous 33 S depletions in IIIF iron meteorites (<−0.02 per mil), and 33 S enrichments in other magmatic iron meteorite groups. The 33 S depletions support the idea that differentiated planetesimals inherited sulfur that was photochemically derived from gases in the early inner solar system (<∼2 AU), and that bulk inner solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content.iron meteorites | sulfur isotopes | protoplanetary disk | solar system | photochemistry O f all of the extraterrestrial materials found on Earth, iron meteorites have always been the most conspicuous. Socalled "magmatic" iron meteorites are likely to be samples from the cores of magmatically differentiated protoplanetary parent bodies (1), whereas "nonmagmatic" iron meteorites are commonly suggested to sample solidified melt pockets that formed via impacts onto nondifferentiated (chondritic) parent bodies (2). Individual members from an iron meteorite group are assumed to derive from a common parent body, based on shared chemical and isotopic characteristics (1-4). Chemical and isotopic differences among the different iron groups provide convincing evidence that different individual parent body planetesimals incorporated genetically distinct precursor materials (1-4).Recent observations that several achondrite meteorite groups possess small, mass-independent 33 S enrichments relative to chondrites (5) have led to the conclusion that sulfur isotopes were heterogeneously distributed among the materials that accreted to form early solar system planetesimals. This observation, coupled with the ancient 182 Hf-182 W ages (within 1-3 My of solar system formation) of magmatic irons (6-8), provides impetus to search for systematic variations in mass-independent sulfur isotope compositions among the iron groups. ResultsWe report high-precision δ 34 S, Δ 33 S, and Δ 36 S data (where Δ 33 S = 1000 × {δ 33 S -[(δ 34 S + 1) 0.515 − 1]} and Δ 36 S = 1000 × {δ 36 S -[(δ 34 S + 1) 1.9 − 1]}) for 61 troilite (FeS) nodules extracted from 58 different iron meteorites selected from eight different groups (IAB, IC, IIAB, IIE, IIIAB, IIIF, IVA, and IVB) (Fig. 1, Fig. S1, and Tables S1 and S2). All groups except for IAB and IIE have been classi...

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“…The composition of the initial gas phase of the disk is defined as follows: we assume that the abundances of all elements, including oxygen, are protosolar 38 and that O, C, and [39][40][41][42] In addition, S is assumed to exist in the form of H 2 S, with H 2 S/H 2 = 0.5 × (S/H 2 ) ⊙ 1 , and other refractory sulfide components. 43 We also consider N 2 /NH 3 = 10/1 in the nebula gas-phase, a value compatible with thermochemical models of the solar nebula 44 and with observations of cometary comae. 27 In the following, we adopt these mixing ratios as our nominal model of the solar nebula gas phase composition (see Table 1).…”

Section: Formation Of Clathrates In the Primordial Nebulamentioning

confidence: 86%

Volatile inventories in clathrate hydrates formed in the primordial nebula

et al. 2010

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Examination of ambient thermodynamic conditions suggest that clathrate hydrates could exist in the martian permafrost, on the surface and in the interior of Titan, as well as in other icy satellites. Clathrate hydrates probably formed in a significant fraction of planetesimals in the solar system. Thus, these crystalline solids may have been accreted in comets, in the forming giant planets and in their surrounding satellite systems. In this work, we use a statistical thermodynamic model to investigate the composition of clathrate hydrates that may have formed in the primordial nebula. In our approach, we consider the formation sequence of the different ices occurring during the cooling of the nebula, a reasonable idealization of the process by which volatiles are trapped in planetesimals. We then determine the fractional occupancies of guests in each clathrate hydrate formed at given temperature. The major ingredient of our model is the description of the guest-clathrate hydrate interaction by a spherically averaged Kihara potential with a nominal set of parameters, most of which being fitted on experimental equilibrium data. Our model allows us to find that Kr, Ar and N 2 can be efficiently encaged in clathrate hydrates formed at temperatures higher than ∼ 48.5 K in the primitive nebula, instead of forming pure condensates below 30 K. However, we find at the same time that the determination of the relative abundances of guest species incorporated in these clathrate hydrates strongly depends on the choice of the parameters of the Kihara potential and also on the adopted size of cages. Indeed, testing different potential parameters, we have noted that even minor dispersions between the different existing sets can lead to non-negligible variations in the determination of the volatiles trapped in clathrate hydrates formed in the primordial nebula. However, these variations are not found to be strong enough to reverse the relative abundances between the different volatiles in the clathrate hydrates themselves. On the other hand, if contraction or expansion of the cages due to temperature variations are imposed in our model, the Ar and Kr mole fractions can be modified up to several orders of magnitude in clathrate hydrates. Moreover, mole fractions of other molecules such as N 2 or CO are also subject to strong changes with the variation of the size of the cages. Our results may affect the predictions of the composition of the planetesimals formed in the outer solar system. In particular, the volatile abundances calculated in the giant planets atmospheres should be altered because these quantities are proportional to the mass of accreted and vaporized icy planetesimals. For similar reasons, the estimates of the volatile budgets accreted by icy satellites and comets may also be altered by our calculations. For instance, under some conditions, our calculations predict that the abundance of argon in the atmosphere of Titan should be higher than the value measured by Huygens. Moreover, the Ar abundance in comets...

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Sulfur chemistry with time-varying oxygen abundance during Solar System formation

Cited by 97 publications

References 54 publications

The evolution of the water distribution in a viscous protoplanetary disk

The evolution of the water distribution in a viscous protoplanetary disk

Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets

Volatile inventories in clathrate hydrates formed in the primordial nebula

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