Meteoritic oxide grain from supernova found
Meteoritic oxide grain from supernova found
复制标题
发现来自超新星的陨石氧化物颗粒
作者：
L. Nittler;C. Alexander;J. Wang;X. Gao
陨石含有微小的（0.002-10 μm）矿物颗粒，形成于恒星周围或恒星爆炸中。这些颗粒具有不寻常的同位素组成，反映了它们形成的恒星。由纳米金刚石、碳化硅（SiC）、氮化硅（Si 3 N4）或石墨组成的星尘被认为来自一系列恒星类型，而迄今发现的富氧颗粒被认为只来自红巨星和渐近巨星分支星。我们在这里报告的氧化物颗粒，是非常丰富的同位素氧-16（16 O），在铁希茨陨石的耐酸残留物。这个颗粒，T84，可能来自II型超新星的喷出物，是第一个报道的来自这种来源的氧化物颗粒，尽管16 O是超新星喷出的第三大同位素（仅次于氢和氦）。
Meteorites contain tiny (0.002-10 μm) mineral grains which formed around stars or in stellar explosions,. These grains have unusual isotope compositions that reflect those of the stars in which they formed. Stardust composed of nanodiamonds, silicon carbide (SiC), silicon nitride (Si3N4) or graphite are believed to derive from a range of stellar types,, whereas the oxygen-rich grains found to date are thought to originate only in red giants and asymptotic giant branch stars. We report here an oxide grain that is extremely rich in the isotope oxygen-16 (16O), in an acid-resistant residue of the Tieschitz meteorite. This grain, T84, probably derives from the ejecta of a type II supernova and is the first reported oxide grain derived from such a source, despite 16O being the third most abundant isotope ejected by supernovae (after hydrogen and helium).