The origin of short-lived nuclides in the early solar system: implications for the assembly of terrestrial bodies

早期太阳系中短命核素的起源：对类地天体组装的影响

• 批准号: ST/F002734/1
• 负责人: Timothy Elliott
• 金额: $ 39.06万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FF002734%2F1
• 关键词: origin; short; lived; nuclides; early

Short-lived isotope systems play a critical role in constraining the timescales of early solar system processes. They also potentially finger-print the stellar sources of material in the solar nebular and provide a mechanism for nebular collapse. In all these respects the constraints provided by the very short lived 26Al and 60Fe (with half-lives 0.75 and 1.5My respectively) are key. Furthermore, as major, refractory elements, these extinct isotopes once constituted an essential part of the accreting terrestrial planets and provided a significant early heat source to drive planetary differentiation. Recent work in the Fe-Ni system yield tantalising data, but highlight perennial problems in deconvolving time from initial heterogeneity when interpretting these short-lived systems. In this proposal we will explicitly address these issues by combining new high precision techniques in analysis of Fe-Ni, Al-Mg and U-Pb on same meteoritical objects (CAI and chondrules). We will thus determine the initial 60Fe and 26Al for samples absolutely dated by U-Pb and examine if this differs between meteorites groups. This will allow us to determine the magnitude of any nebular heterogeneity, assess its causes and robustly re-evaluate the chronology of the early solar system.

短命同位素系统在限制早期太阳系过程的时间尺度方面发挥着关键作用。它们还可能对太阳星云中的恒星物质来源进行指纹识别，并提供星云塌缩的机制。在所有这些方面，寿命非常短的 26Al 和 60Fe（半衰期分别为 0.75 和 1.5My）所提供的限制是关键。此外，作为主要的难熔元素，这些灭绝的同位素曾经构成了类地行星吸积的重要组成部分，并为驱动行星分化提供了重要的早期热源。最近在 Fe-Ni 系统中的工作产生了诱人的数据，但在解释这些短暂的系统时，突出了从初始异质性中解卷积时间的长期问题。在本提案中，我们将通过结合新的高精度技术对同一陨石物体（CAI 和球粒）上的 Fe-Ni、Al-Mg 和 U-Pb 进行分析来明确解决这些问题。因此，我们将确定绝对由 U-Pb 测年的样品的初始 60Fe 和 26Al，并检查这在陨石群之间是否存在差异。这将使我们能够确定任何星云异质性的大小，评估其原因并有力地重新评估早期太阳系的年表。

项目成果

NEUTRON-POOR NICKEL ISOTOPE ANOMALIES IN METEORITES

• DOI: 10.1088/0004-637x/758/1/59
• 发表时间: 2012-09
• 期刊: The Astrophysical Journal
• 作者: R. Steele;C. Coath;M. Regelous;S. Russell;T. Elliott

Confirmation of mass-independent Ni isotopic variability in iron meteorites

• DOI: 10.1016/j.gca.2011.08.030
• 发表时间: 2011-12
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: R. Steele;T. Elliott;C. Coath;M. Regelous

Statistical bias in isotope ratios

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.
• 作者: Coath C