论文标题
对F-Giant Star $θ$ Scorpii A的研究：合并后快速旋转器？
A study of the F-giant star $θ$ Scorpii A: a post-merger rapid rotator?
论文作者
论文摘要
我们报告了F1 $ \，$ iii star $θ$ scorpii的线性极化的高精度观测值。偏振具有对快速旋转器的预期形式的波长依赖性，但振幅比其他类似的主要序列恒星大几倍。这证实了这样一种预期，即由于散射与吸收不相形的比率的密度依赖性，低重力恒星应具有更强的旋转偏振特征。通过对极化进行建模，再加上其他观察性约束（包括对河马天文学的修订分析，阐明了系统的二进制状态），我们确定了一组精确的恒星参数，包括旋转率$ω\，（=ω/ω_______________________________________ED0.94 $，polar $，polar $，polar $，polar $，polar $ callity $，polar $ callity $，polar callity $，polar $，polar $，polar callity $，polar callity。 ^{+0.042} _ { - 0.039} $（dex cgs），质量$ 3.10 ^{+0.37} _ { - 0.32} $ solar Masses和Luminosity $ \ log（l/lsun）= 3.149 ^{+0.041} ^{+0.041} _ {+0.041} _ {-0.0028} $ {-0.028} $。这些值与单个旋转恒星的进化模型不兼容，恒星的进化阶段太快旋转，并且对其发光度不足。我们得出的结论是，$θ$ SCO A很可能是二进制合并的产物。
We report high-precision observations of the linear polarization of the F1$\,$III star $θ$ Scorpii. The polarization has a wavelength dependence of the form expected for a rapid rotator, but with an amplitude several times larger than seen in otherwise similar main-sequence stars. This confirms the expectation that lower-gravity stars should have stronger rotational-polarization signatures as a consequence of the density dependence of the ratio of scattering to absorption opacities. By modelling the polarization, together with additional observational constraints (incorporating a revised analysis of Hipparcos astrometry, which clarifies the system's binary status), we determine a set of precise stellar parameters, including a rotation rate $ω\, (= Ω/Ω_{\rm c})\ge 0.94$, polar gravity $\log{g_p} = 2.091 ^{+0.042}_{-0.039}$ (dex cgs), mass $3.10 ^{+0.37}_{-0.32}$ solar masses, and luminosity $\log(L/Lsun) =3.149^{+0.041}_{-0.028}$. These values are incompatible with evolutionary models of single rotating stars, with the star rotating too rapidly for its evolutionary stage, and being undermassive for its luminosity. We conclude that $θ$ Sco A is most probably the product of a binary merger.
