Origin of meteoritic stardust unveiled by a revised proton-capture rate of 17O
Origin of meteoritic stardust unveiled by a revised proton-capture rate of 17O
复制标题
修改后的 17O 质子捕获率揭示了陨石星尘的起源
DOI：
10.1038/s41550-016-0027
复制
发表时间：
2017
期刊：
影响因子：
14.1
通讯作者：
D. Trezzi
中科院分区：
文献类型：
--
作者：
M. Lugaro;A. Karakas;C. Bruno;M. Aliotta;L. Nittler;D. Bemmerer;A. Best;A. Boeltzig;C. Broggini;A. Caciolli;F. Cavanna;G. Ciani;P. Corvisiero;T. Davinson;R. Depalo;A. Di Leva;Z. Elekes;F. Ferraro;A. Formicola;Z. Fülöp;G. Gervino;A. Guglielmetti;C. Gustavino;G. Gyürky;G. Imbriani;M. Junker;R. Menegazzo;V. Mossa;F. Pantaleo;D. Piatti;P. Prati;D. Scott;O. Straniero;F. Strieder;T. Szücs;M. P. Tak'acs;D. Trezzi
从陨石中回收的星尘颗粒提供了它们形成时恒星环境同位素组成的高精度快照。然而，将它们的起源归因于特定类型的恒星往往是困难的。4-8太阳质量的中等质量恒星预计贡献了很大一部分陨星尘埃2,3。然而，还没有发现具有这类恒星所期望的特征同位素组成的颗粒。这是一个长期存在的谜题，它指出了我们对银河系中恒星和尘埃生命周期的理解存在严重差距。在这里，我们表明，最近的地下实验报告的17O质子捕获率增加6导致17O/16O同位素比与在质子燃烧温度为60-80 MK的星尘颗粒中观察到的结果相匹配。这些温度是在4-8太阳质量的中等质量恒星的后期演化过程中对流包膜的底部达到的7 - 9，这表明它们是最可能的颗粒起源地点。这一结果提供了直接的证据，证明这些恒星对形成太阳系的尘埃有贡献。星尘的同位素分析还没有为它找出一个特定的恒星起源。对17O质子捕获率的修正有助于确定中等质量恒星（4-8个太阳质量）是大部分流星星尘的来源。
Stardust grains recovered from meteorites provide high-precision snapshots of the isotopic composition of the stellar environment in which they formed1. Attributing their origin to specific types of stars, however, often proves difficult. Intermediate-mass stars of 4–8 solar masses are expected to have contributed a large fraction of meteoritic stardust2,3. Yet, no grains have been found with the characteristic isotopic compositions expected for such stars4,5. This is a long-standing puzzle, which points to serious gaps in our understanding of the lifecycle of stars and dust in our Galaxy. Here we show that the increased proton-capture rate of 17O reported by a recent underground experiment6 leads to 17O/16O isotopic ratios that match those observed in a population of stardust grainsfor proton-burning temperatures of 60–80 MK. These temperatures are achieved at the base of the convective envelope during the late evolution of intermediate-mass stars of 4–8 solar masses7–9, which reveals them as the most likely site of origin of the grains. This result provides direct evidence that these stars contributed to the dust inventory from which the Solar System formed. Isotopic analyses of stardust have yet to single out a specific stellar origin for it. A revision of the proton-capture rate of 17O has helped to identify intermediate mass stars (4–8 solar masses) as the source of a large fraction of meteoritic stardust.