New Constraints on the Abundance of 60Fe in the Early Solar System
New Constraints on the Abundance of 60Fe in the Early Solar System
复制标题
早期太阳系中60Fe丰度的新限制
DOI：
10.3847/2041-8213/aabba9
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
G. Huss
中科院分区：
文献类型：
--
作者：
R. Trappitsch;P. Boehnke;T. Stephan;M. Telus;M. Savina;O. Pardo;A. Davis;N. Dauphas;M. Pellin;G. Huss
确定早期太阳系中已灭绝的放射性核素60Fe（半衰期2.62 Ma）的丰度对于理解太阳系形成的天体物理背景具有重要意义。虽然对太阳系早期阶段的大量测量显示出与银河系背景相符的低丰度，但通过二次离子质谱（SIMS）进行的一些原位测量显示出更高的丰度，这需要附近的超新星（SN）注入。本文采用共振电离质谱法（RIMS）对原始陨石Semarkona （LL3.00）的球粒进行了原位镍同位素分析。同样的球粒之前已经被SIMS分析过。尽管与SIMS相比精度有所提高，但RIMS的镍同位素数据并没有显示出任何可以明确归因于原位60Fe衰变的60Ni过量。60Ni/58Ni与56Fe/58Ni的线性回归得到60Fe/56Fe的初始比值为（3.8±6.9）× 10−8，这与大量测量发现的低初始值和从一些原位工作推断的初始比值范围的低端一致。同样的回归也给出了太阳初始60Ni/58Ni比，这表明该样品没有受到镍动员的干扰，因此符合低初始60Fe/56Fe比。这些发现与先前对同一样本的SIMS测量结果的重新评估一致。因此，超新星向太阳系或其母云物质中注入的60Fe对于测量到的太阳系初始60Fe量来说是没有必要的。
Establishing the abundance of the extinct radionuclide 60Fe (half-life 2.62 Ma) in the early solar system is important for understanding the astrophysical context of solar system formation. While bulk measurements of early solar system phases show a low abundance consistent with galactic background, some in situ measurements by secondary ion mass spectrometry (SIMS) imply a higher abundance, which would require injection from a nearby supernova (SN). Here we present in situ nickel isotopic analyses by resonance ionization mass spectrometry (RIMS) in a chondrule from the primitive meteorite Semarkona (LL3.00). The same chondrule had been previously analyzed by SIMS. Despite improved precision compared to SIMS, the RIMS nickel isotopic data do not reveal any resolved excesses of 60Ni that could be unambiguously ascribed to in situ 60Fe decay. Linear regression of 60Ni/58Ni versus 56Fe/58Ni yields an initial 60Fe/56Fe ratio for this chondrule of (3.8 ± 6.9) × 10−8, which is consistent with both the low initial value found by bulk measurements and the low end of the range of initial ratios inferred from some in situ work. The same regression also gives a solar initial 60Ni/58Ni ratio, which shows that this sample was not disturbed by nickel mobilization, thus agreeing with a low initial 60Fe/56Fe ratio. These findings agree with a re-evaluation of previous SIMS measurements of the same sample. Supernova injection of 60Fe into the solar system or its parental cloud material is therefore not necessary to account for the measured solar system’s initial amount of 60Fe.
同位素比率的统计偏差
DOI：
10.1039/c2ja10205f
发表时间：
2013
期刊：
J. Anal. At. Spectrom.
影响因子：
--
作者：
Coath C
通讯作者：
Coath C