Wide-Band Optical Filter Optimized for Deep Imaging of Small Solar-System Bodies

AbstractUnderstanding the true nature of extra-terrestrial water and organic matter that were present at the birth of our solar system, and their subsequent evolution, necessitates the study of pristine astromaterials. In this study, we have studied both the water and organic contents from a dust particle recovered from the surface of near-Earth asteroid 25143 Itokawa by the Hayabusa mission, which was the first mission that brought pristine asteroidal materials to Earth’s astromaterial collection. The organic matter is presented as both nanocrystalline graphite and disordered polyaromatic carbon with high D/H and 15N/14N ratios (δD = + 4868 ± 2288‰; δ15N = + 344 ± 20‰) signifying an explicit extra-terrestrial origin. The contrasting organic feature (graphitic and disordered) substantiates the rubble-pile asteroid model of Itokawa, and offers support for material mixing in the asteroid belt that occurred in scales from small dust infall to catastrophic impacts of large asteroidal parent bodies. Our analysis of Itokawa water indicates that the asteroid has incorporated D-poor water ice at the abundance on par with inner solar system bodies. The asteroid was metamorphosed and dehydrated on the formerly large asteroid, and was subsequently evolved via late-stage hydration, modified by D-enriched exogenous organics and water derived from a carbonaceous parent body.

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Microstructural features in carbonates from Antarctic micrometeorites: Effective tools for analyzing the evolution of small Solar System bodies

Microscopy and Microanalysis ◽

10.1017/s1431927621009740 ◽

2021 ◽

Vol 27 (S1) ◽

pp. 2778-2781

Author(s):

Elena Dobrica ◽

Kenta Ohtaki ◽

Cecile Engrand

Keyword(s):

Solar System ◽

Solar System Bodies

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The Grand Tack model: a critical review

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314008254 ◽

2014 ◽

Vol 9 (S310) ◽

pp. 194-203 ◽

Cited By ~ 12

Author(s):

Sean N. Raymond ◽

Alessandro Morbidelli

Keyword(s):

Solar System ◽

Building Blocks ◽

Protoplanetary Disk ◽

Giant Planets ◽

Asteroid Belt ◽

Terrestrial Planets ◽

Saturn’S Satellites ◽

Internal Inconsistency ◽

Solar System Bodies ◽

Gas Accretion

AbstractThe “Grand Tack” model proposes that the inner Solar System was sculpted by the giant planets' orbital migration in the gaseous protoplanetary disk. Jupiter first migrated inward then Jupiter and Saturn migrated back outward together. If Jupiter's turnaround or “tack” point was at ~ 1.5 AU the inner disk of terrestrial building blocks would have been truncated at ~ 1 AU, naturally producing the terrestrial planets' masses and spacing. During the gas giants' migration the asteroid belt is severely depleted but repopulated by distinct planetesimal reservoirs that can be associated with the present-day S and C types. The giant planets' orbits are consistent with the later evolution of the outer Solar System.Here we confront common criticisms of the Grand Tack model. We show that some uncertainties remain regarding the Tack mechanism itself; the most critical unknown is the timing and rate of gas accretion onto Saturn and Jupiter. Current isotopic and compositional measurements of Solar System bodies – including the D/H ratios of Saturn's satellites – do not refute the model. We discuss how alternate models for the formation of the terrestrial planets each suffer from an internal inconsistency and/or place a strong and very specific requirement on the properties of the protoplanetary disk.We conclude that the Grand Tack model remains viable and consistent with our current understanding of planet formation. Nonetheless, we encourage additional tests of the Grand Tack as well as the construction of alternate models.

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