论文标题
比较由h $α$拟合和重力变暗确定的恒星倾斜角
Comparing Be Star Inclination Angles Determined from H$α$ Fitting and Gravitational Darkening
论文作者
论文摘要
使用92个银河为恒星的样品，我们比较了倾斜角（恒星旋转轴和视线之间的角度）从H $α$发射线曲线拟合确定的，与由重力变暗的光谱签名确定的倾斜角度。我们发现良好的一致性：70％的样本（92颗星中的64个）与使用$1σ$错误之间的两种方法之间的差零差一致，并且两种方法的$ r =+0.63 \ pm0.05 $之间存在强的线性相关系数。有一些证据表明，H $α$配置拟合方法高估了$ i \ i \ Lessim 25^\ Circ $的倾角角，也许是由于忽略了H $α$α$α$线宽度上不相互电的电子散射，而重力变暗的方法可能会导致$ i \ gtrsim70^的倾斜度的转移，这可能是nive \ gtrsim70^$ cir的转移。 光谱。总体而言，可以证明，单个h $α$ snr的频谱可用于提取单个是恒星的倾斜角度的有用估计值。这允许单个恒星的赤道旋转速度从$ v \ sin i $测量中得出，并且如果使用无偏见（相对于倾斜度）BE恒星的样本，则可以使用恒星来搜索年轻的，开放式簇中的相关旋转轴。
Using a sample of 92 Galactic Be stars, we compare inclination angles (the angle between a star's rotation axis and the line-of-sight) determined from H$α$ emission line profile fitting to those determined by the spectroscopic signature of gravitational darkening. We find good agreement: 70% of the sample (64 out of 92 stars) is consistent with zero difference between the two methods using $1σ$ errors, and there is a strong linear correlation coefficient between the two methods of $r=+0.63\pm0.05$. There is some evidence that the H$α$ profile fitting method overestimates the inclination angle for $i\lesssim 25^\circ$, perhaps due to the neglect of incoherent electron scattering on the H$α$ line widths, while the gravitational darkening method underestimates the inclination angle for $i\gtrsim70^\circ$, perhaps due to the neglect of disk radiative transfer effects on the optical spectrum. Overall, it is demonstrated that a single H$α$ spectrum of modest resolution and SNR can be used to extract a useful estimate for the inclination angle of an individual Be star. This allows equatorial rotation velocities for individual Be stars to be derived from $v \sin i $ measurements and will allow Be stars to be used to search for correlated spin axes in young, open clusters if unbiased (with respect to inclination) samples of Be stars are used.
