论文标题
UV CET的无线电发射：恒星磁层的极光发射
Radio Emission from UV Cet: Auroral Emission from a Stellar Magnetosphere
论文作者
论文摘要
Meerkat在2021年10月5日至6日观察到了原型的耀斑星UV CET。在886-1682 MHz之间观察到，持续时间为$ \ sim \！2 $ hr，其时间分辨率为8s，频率分辨率为8s，频率分辨率为0.84 MHz，可充满活力的动态光谱。发射的特征是三个峰，其中包含频率域中的宽带弧或部分弧。通常，弧度是高度右圆两极化的。在第三个峰的结尾，发生了短暂的爆发，这些突发呈椭圆极化。我们提出了一个简单的模型，该模型似乎与UV CET的无线电发射的特性大致一致。简而言之，恒星磁场被建模为与恒星旋转轴对齐的偶极子。假定无线电发射机制是由于回旋子摩泽的不稳定性引起的，其中X模式辐射在电子陀螺仪附近被放大。虽然椭圆极化的爆发可能与源具有固有的固有性，但对源和沿传播路径的血浆密度施加了严格的限制。我们建议，椭圆极化的辐射可能是在距离源距离一定距离的过度密度等离子体结构上反射的结果。 UV〜CET的无线电发射具有恒星和行星属性。
The archetypical flare star UV Cet was observed by MeerKAT on 5-6 October 2021. A large radio outburst with a duration of $\sim\!2$ hr was observed between 886-1682 MHz with a time resolution of 8s and a frequency resolution of 0.84 MHz, enabling sensitive dynamic spectra to be formed. The emission is characterized by three peaks containing a multitude of broadband arcs or partial arcs in the time-frequency domain. In general, the arcs are highly right-hand circularly polarized. During end of the third peak, brief bursts occur that are significantly elliptically polarized. We present a simple model that appears to be broadly consistent with the characteristics of the radio emission from UV Cet. Briefly, the stellar magnetic field is modeled as a dipole aligned with the rotational axis of the star. The radio emission mechanism is assumed to be due to the cyclotron maser instability where x-mode radiation near the electron gyrofrequency is amplified. While the elliptically polarized bursts may be intrinsic to the source, rather stringent limits are imposed on the plasma density in the source and along the propagation path. We suggest that the elliptically polarized radiation may instead be the result of reflection on an over-dense plasma structure at some distance from the source. Radio emission from UV~Cet shares both stellar and planetary attributes.
