论文标题
重新审视的樱赖的对象：碳酸盐和梅利特岩的新实验室数据表明6.9 $ $ m $ m多余的吸收的载体是碳酸盐
Sakurai's Object revisited: new laboratory data for carbonates and melilites suggest the carrier of 6.9 $μ$m excess absorption is a carbonate
论文作者
论文摘要
我们提供新的房间温度1100-1800 cm^{ - 1}硅酸盐硅酸盐和600-2000 cm^{ - 1}光谱的三种随机定向的细粒碳酸盐的光谱，以确定6.9 〜micron吸收的可能的载体（S）在包括多种密集的年轻天文学对象中观察到的6.9 〜microctoption特征。我们专注于低质量后的Agb恒星Sakurai的物体，该物体自1990年代发生喷发事件以来一直在形成大量的碳尘。大型Melilite晶粒不对6.9微米的吸收特征负责，因为实验室光谱中的类似形状的特征是由非常低（0.1％的碳酸盐）污染产生的，该特征在其他波长下未检测到。由于碳酸盐中的6.9微米特征的较高的带长度，我们得出结论，碳酸盐含有天文学6.9〜微米的特征。用樱赖物体模型中的碳酸盐代替Melilite可以改善与6-7微米的Spitzer光谱的拟合，而没有显着改变Bowey先前模型的其他结论，只是陨石中的特征和丰富度之间没有联系。使用镁铁矿（MGCO3），25微米大小的SIC晶粒的丰度增加了10-50％，并且更好地限制了。碳酸盐灰尘的质量类似于PAH灰尘的质量。现有的实验表明碳酸盐稳定在700〜K以下，但是很难确定这些实验对天文环境的适用性，并且需要更多的研究。
We present new room-temperature 1100 - 1800 cm^{-1} spectra of melilite silicates and 600 - 2000 cm^{-1} spectra of three randomly orientated fine-grained carbonates to determine the possible carrier(s) of a 6.9~micron absorption feature observed in a variety of dense astronomical environments including young stellar objects and molecular clouds. We focus on the low-mass post-AGB star Sakurai's Object which has been forming substantial quantities of carbonaceous dust since an eruptive event in the 1990s. Large melilite grains cannot be responsible for the 6.9-micron absorption feature because the similarly-shaped feature in the laboratory spectrum was produced by very low (0.1 per cent by mass) carbonate contamination which was not detected at other wavelengths. Due to the high band-strength of the 6.9-micron feature in carbonates, we conclude that carbonates carry the astronomical 6.9~micron feature. Replacement of melilite with carbonates in models of Sakurai's object improves fits to the 6 - 7-micron Spitzer spectra without significantly altering other conclusions of Bowey's previous models except that there is no link between the feature and the abundance of melilite in meteorites. With magnesite (MgCO3), the abundance of 25-micron-sized SiC grains is increased by 10 - 50 per cent and better constrained. The mass of carbonate dust is similar to the mass of PAH dust. Existing experiments suggest carbonates are stable below 700~K, however it is difficult to ascertain the applicability of these experiments to astronomical environments and more studies are required.
