论文标题
锂和铍在一个太阳质量星中
Lithium and Beryllium in One Solar Mass Stars
论文作者
论文摘要
恒星中锂（Li）和铍（BE）的表面含量可以揭示有关其内部区域温度结构和物理过程的重要信息。这项研究的重点是具有比以前更精确定义的样品的太阳能型星。我们研究为BE研究的恒星的选择受到五个参数的约束：质量，温度，表面重力，金属性和年龄与太阳相似，并集中在1 m_sun的 +-0.02之内的恒星。我们已经使用了带有员工的凯克I望远镜来获得高光谱分辨率（$ \ sim $ 45,000）和高信噪比的52颗恒星的BE II光谱区域。尽管这些恒星中的LI中的扩散大于400倍，但BE中的扩散仅为2.7倍。两颗恒星没有任何东西，也许是由于与同伴的合并或传质。我们发现LI温度的陡峭趋势，但几乎没有BE。虽然由于出色的耗竭，[fe/h]的下降趋势从-0.4到+0.4，但银河系中的Fe富集的Be量很小。尽管随着年龄的增长，LI的下降幅度很大，但随着年龄的增长，BE可能会少了，尽管年龄不确定。在温度和其他参数最接近太阳的恒星子集中，我们发现BE与Li的丰度比模型所预测的要低得多。可能还有其他混合机制导致额外的LI耗竭。
The surface content of lithium (Li) and beryllium (Be) in stars can reveal important information about the temperature structure and physical processes in their interior regions. This study focuses on solar-type stars with a sample that is more precisely defined than done previously. Our selection of stars studied for Be is constrained by five parameters: mass, temperature, surface gravity, metallicity, and age to be similar to the Sun and is focussed on stars within +-0.02 of 1 M_sun. We have used the Keck I telescope with HIRES to obtain spectra of the Be II spectral region of 52 such stars at high spectral resolution ($\sim$45,000) and high signal-to-noise ratios. While the spread in Li in these stars is greater than a factor of 400, the spread in Be is only 2.7 times. Two stars were without any Be, perhaps due to a merger or a mass transfer with a companion. We find a steep trend of Li with temperature but little for Be. While there is a downward trend in Li with [Fe/H] from -0.4 to +0.4 due to stellar depletion, there is a small increase in Be with Fe from Galactic Be enrichment. While there is a broad decline in Li with age, there may be a small increase in Be with age, though age is less well-determined. In the subset of stars closest to the Sun in temperature and other parameters we find that the ratio of the abundances of Be to Li is much lower than predicted by models; there may be other mixing mechanisms causing additional Li depletion.
