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A fundamental puzzle of our solar systems formation is understanding why the terrestrial bodies including the planets,comets,and asteroids are depleted in $^{16}$O compared to the Sun. The most favored mechanism,the selective photodissociation of CO gas to produce $^{16}$O depleted water,requires finely tuned mixing timescales to transport $^{16}$O depleted water from the cold outer solar system to exchange isotopically with dust grains to produce the $^{16}$O depleted planetary bodies observed today. Here we show that energetic particle irradiation of SiO$_2$ (and Al$_2$O$_3$) makes them susceptible to anomalous isotope exchange with H$_2$O ice at temperatures as low as 10 K. The observed magnitude of the anomalous isotope exchange (D$^{17}$O) is sufficient to generate the $^{16}$O depletion characteristic of the terrestrial bodies in the solar system. We calculated the cosmic-ray exposure times needed to produce the observed $^{16}$O depletions in silicate (SiO2) dust in the interstellar medium and early solar system and find that radiation damage induced oxygen isotope exchange could have rapidly (~10-100 yrs) depleted dust grains of $^{16}$O during the Suns T-Tauri phase. Our model explains whythe oldest and most refractory minerals found in the solar system, the anhydrous Calcium with Aluminum Inclusions (CAIs),are generally $^{16}$O enriched compared to chondrules and the bulk terrestrial solids and provides a mechanism for producing $^{16}$O depleted grains very early in the solar systems history. Our findings have broad implications for the distribution of oxygen isotopes in the solar system, the interstellar medium, the formation of the planets and its building blocks as well as the nature of mass-independent isotope effects.
Under current conditions, the cosmic ray spectrum incident on the Earth is dominated by particles with energies < 1 GeV. Astrophysical sources including high energy solar flares, supernovae and gamma ray bursts produce high energy cosmic rays (HECRs)
In the early 1990s, contemporary interstellar dust (ISD) penetrating deep into the heliosphere was identified with the in-situ dust detector on board the Ulysses spacecraft. Between 1992 and the end of 2007 Ulysses monitored the ISD stream. The inter
I make publicly available my literature study into carbon isotope ratios in the Solar System, which formed a part of Woods & Willacy (2009). As far as I know, I have included here all measurements of 12C/13C in Solar System objects (excluding those o
The presence of excesses of short-lived radionuclides in the early solar system evidenced in meteorites has been taken as testament to close encounters with exotic nucleosynthetic sources, including supernovae or AGB stars. An analysis of the likelih
Experimental and theoretical state-selective X-ray spectra resulting from single-electron capture in charge exchange (CX) collisions of Ne^10+ with He, Ne, and Ar are presented for a collision velocity of 933 km s^-1 (4.54 keV nucleon^-1), comparable