论文标题
M9.5矮人BRI 0021-0214的光学变异性，旋转周期和倾斜角
Optical Variability, Rotation Period and Inclination Angle of the M9.5 dwarf BRI 0021-0214
论文作者
论文摘要
我们报告了无线电检测的M9.5矮人BRI 0021-0214的$ i $ - 带光度观测，该观察是在180万梵蒂冈高级技术望远镜Vatt上使用的Glaway Ultra Fast Fast Imager（GUFI）在亚利桑那州Graham International Perstervatory的180万个先进技术望远镜Vatt获得的。总共获得了73天基线的19个小时观测。显示BRI 0021-0214显示出$ 3.052 \ pm 0.004 $小时，平均振幅可变性为0.0044 mag，其周期为$ 3.052 \ pm 0.004 $。当与以前的工作中获得的旋转速度数据结合使用时，我们新发现的旋转周期的倾斜角为51.7 $^{+5.0} _ { - 4.5} $度对于BRI 0021-0214的旋转轴相对于我们的视线而言。先前的研究报告说，该矮人的光学变异性最合理的原因是其大气中悬挂的共旋转尘埃云的结果。然而，增强的H $_α$和间歇性相干无线电发射的报道表明，其磁层可能具有极光活性。此外，该矮人的更协调的多波长度观察可以完全解决这种难以捉摸的快速旋转对象的观察特性的性质。
We report $I$-band photometric observations of the radio-detected M9.5 dwarf BRI 0021-0214, obtained with the Galway Ultra Fast Imager (GUFI) on the 1.8m Vatican Advanced Technology Telescope VATT at Mt. Graham International Observatory, Arizona. In total, 19 hours of observations over a 73 day baseline were obtained. BRI 0021-0214 was shown to exhibit modulated emission with a period of $ 3.052 \pm 0.004$ hours with a mean amplitude variability of 0.0044 mag. When combined with rotational velocity data obtained from previous work, our newly discovered rotation period gives an inclination angle of 51.7$^{+5.0}_{-4.5}$ degrees for the rotation axis of BRI 0021-0214 relative to our line of sight. Previous studies have reported that the most plausible cause for optical variability from this dwarf is a consequence of suspended co-rotating dust clouds in its atmosphere. However reports of enhanced H$_α$ and intermittent coherent radio emission suggest the possibility of auroral activity in its magnetosphere. Further, more coordinated multiwavlength observations of this dwarf could fully resolve the nature of this elusive rapid-rotator object's observational properties.
