标题： 放射性铁雨：将超新星尘埃中的$^{60}$Fe 输送到海底的运输 显示英文标题

标题： Radioactive Iron Rain: Transporting $^{60}$Fe in Supernova Dust to the Ocean Floor

摘要： 多个搜索发现了$^{60}$铁沉积的证据，可能是来自近地超新星（SN）的沉积物，在地球不同位置的浓度有所不同。 本文研究了携带$^{60}$铁的星际尘埃从 SN 经过日球层时的各种影响因素，旨在估算其最终在海底的全球分布。 我们研究了磁场、到达角度、风和 SN 物质在海洋中的循环对不同地点浓度的影响。 我们发现 SN 物质通过中间层/低热层（MLT）是影响最终全球分布的最大因素，而当 SN 物质沉降到海底时，海洋循环引起的改变较小。 以前的研究中假设均匀分布的 SN 距离估计是一个很好的近似值。 考虑到表面分布的影响，我们估计一个$8-10 \ M_{\odot}$的 SN 原恒星距离为$46^{+10}_{-6}$pc。 这与 SN 在 $\sim$2.8 百万年前发生在图尔-霍尔星团内一致，SN 物质在 $\sim$2.2 百万年前到达地球。 我们注意到，SN 尘埃在其到达太阳系内部时保留了方向信息，精确度在$1^{\circ}$以内，因此 SN 废料在惰性天体如月球上的沉积将是各向异性的，从而原则上可用于推断方向信息。 特别是，我们预测现有的月球样本应显示出可测量的$^{60}$Fe 差异。 显示英文摘要

摘要： Several searches have found evidence of $^{60}$Fe deposition, presumably from a near-Earth supernova (SN), with concentrations that vary in different locations on Earth. This paper examines various influences on the path of interstellar dust carrying $^{60}$Fe from a SN through the heliosphere, with the aim of estimating the final global distribution on the ocean floor. We study the influences of magnetic fields, angle of arrival, wind and ocean cycling of SN material on the concentrations at different locations. We find that the passage of SN material through the mesosphere/lower thermosphere (MLT) is the greatest influence on the final global distribution, with ocean cycling causing lesser alteration as the SN material sinks to the ocean floor. SN distance estimates in previous works that assumed a uniform distribution are a good approximation. Including the effects on surface distributions, we estimate a distance of $46^{+10}_{-6}$ pc for a $8-10 \ M_{\odot}$ SN progenitor. This is consistent with a SN occurring within the Tuc-Hor stellar group $\sim$2.8 Myr ago with SN material arriving on Earth $\sim$2.2 Myr ago. We note that the SN dust retains directional information to within $1^{\circ}$ through its arrival in the inner Solar System, so that SN debris deposition on inert bodies such as the Moon will be anisotropic, and thus could in principle be used to infer directional information. In particular, we predict that existing lunar samples should show measurable $^{60}$Fe differences.