DECODING THE MESSAGE FROM METEORITIC STARDUST SILICON CARBIDE GRAINS
نویسندگان
چکیده
منابع مشابه
Extinct technetium in silicon carbide stardust grains: implications for stellar nucleosynthesis.
The isotopic composition of ruthenium (Ru) in individual presolar silicon carbide (SiC) stardust grains bears the signature of s-process nucleosynthesis in asymptotic giant branch stars, plus an anomaly in 99Ru that is explained by the in situ decay of technetium isotope 99Tc in the grains. This finding, coupled with the observation of Tc spectral lines in certain stars, shows that the majority...
متن کاملOxygen-rich Stardust Grains from Novae
Stardust grains which have condensed from nova ejecta are exceedingly rare in meteorites. Principally through proton captures, novae are efficient producers of the stable isotopes 13 C, 15 N, and 17 O, as well as radioactive isotopes such as 22 Na and 26 Al. To date, primarily carbonaceous phases of stardust grains (e.g., SiC and graphite), have been purported to have a nova origin. Conversely,...
متن کاملIron and Nickel Isotopic Compositions of Silicon Carbide Z Grains
Introduction: Most presolar SiC grains (~93%) have Si isotopic ratios that fall along the so-called mainstream correlation line of 1.37 on a Si three isotope plot [1]. Z grains, which constitute only ~1% of the total presolar SiC population, plot on the 30 Si-rich side of this line and typically have negative δ 29 Si/ 28 Si values, suggesting that they originated in asymptotic giant branch star...
متن کاملSilicon Carbide Grains of Type X and Supernova Nucleosynthesis
Silicon carbide grains of type X constitute ~1% of all presolar SiC grains found in primitive meteorites. These grains have N and Si excesses, mostly light C, high inferred Al/Al ratios, and evidence (from Ca and Ti excesses) for the initial presence of the short-lived radioisotopes Ti and V. These isotopic signatures clearly indicate an origin in the ejecta of Type II supernovae (SNe) and mate...
متن کاملInfrared spectra of meteoritic SiC grains
We present here the first infrared spectra of meteoritic SiC grains. The mid-infrared transmission spectra of meteoritic SiC grains isolated from the Murchison meteorite were measured in the wavelength range 2.5–16.5 μm, in order to make available the optical properties of presolar SiC grains. These grains are most likely stellar condensates with an origin predominately in carbon stars. Measure...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2013
ISSN: 2041-8205,2041-8213
DOI: 10.1088/2041-8205/768/1/l19