关于Achernar旋转扁率的确定
On the Determination of the Rotational Oblateness of Achernar
摘要：
最近对Achernar的干涉研究得出的结论是，它的几何扁率不能用罗氏近似来解释，鉴于它在恒星天体物理学的许多领域中的潜在影响，引起了社会的极大兴趣。本文的目的是重新解释干涉测量观测结果，其中一颗快速旋转、重力变暗的中央恒星被一个小赤道盘包围，其存在与同期的光谱数据一致。我们发现，我们只能拟合现有的数据假设一个临界旋转的中心恒星。我们确定了两种不同的圆盘模型，它们同时适合光谱、偏振和干涉观测约束：处于流体静力平衡的稀薄圆盘（即，具有小的比例高度）和更小的比例高度增强的盘。我们相信，这些相对较小的圆盘对应于光球和星周环境之间的过渡区，它们可能受到某些光球机制的扰动。近临界旋转体光球层和星周盘之间的界面的研究对于我们理解Be现象以及一般恒星的质量和角动量损失至关重要。这项工作表明，它是现在可以直接研究这个过渡区，同时多技术的观测。
英文摘要：
The recent interferometric study of Achernar, leading to the conclusion that its geometrical oblateness cannot be explained in the Roche approximation, has stirred substantial interest in the community, in view of its potential impact in many fields of stellar astrophysics. It is the purpose of this paper to reinterpret the interferometric observations with a fast rotating, gravity darkened central star surrounded by a small equatorial disk, whose presence is consistent with contemporaneous spectroscopic data. We find that we can only fit the available data assuming a critically rotating central star. We identified two different disk models that simultaneously fit the spectroscopic, polarimetric, and interferometric observational constraints: a tenuous disk in hydrostatic equilibrium (i.e., with small scaleheight) and a smaller, scaleheight enhanced disk. We believe that these relatively small disks correspond to the transition region between the photosphere and the circumstellar environment, and that they are probably perturbed by some photospheric mechanism. The study of this interface between photosphere and circumstellar disk for near-critical rotators is crucial to our understanding of the Be phenomenon, and the mass and angular momentum loss of stars in general. This work shows that it is nowadays possible to directly study this transition region from simultaneous multi-technique observations.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
