Parkes observations for project P1119 semester 2021APRS_01

Recently, low-frequency periodic radio pulses have been detected from the prototypical M-dwarf flare star, UV Ceti. This shows that the low-frequency emission from this star is driven by auroral activity, in stark contrast to the solar-like coronal activity exhibited at microwave–X-ray wavelengths. However, the driver of this auroral activity is unclear. Possible drivers of this aurora include breakdown of co-rotation with a magnetospheric plasma disk, or the sub-Alfv\'enic interaction of the star with a companion planet. Expected signatures of the latter mechanism include small deviations of the radio pulse period from the stellar rotation period, or a modulation of the pulsed radio emission at the planetary orbital period. To detect these signatures, we require long-term, wide-band monitoring of the radio pulses. In this proposal, we seek to accurately measure the pulse rotation period of UV Ceti by measuring the pulse arrival times over four epochs separated by timescales of days--weeks. This will form an important part of the groundwork for detecting signatures of the auroral engine in future long-term monitoring. If successful, this project may constitute the first steps toward unveiling the signature of star-planet interaction in this benchmark M-dwarf.

最近，从典型M型矮星耀星（prototypical M-dwarf flare star）UV Ceti中检测到了低频周期性射电脉冲。这表明该恒星的低频辐射由极光活动（auroral activity）驱动，与微波至X射线波段所呈现的类太阳日冕活动（solar-like coronal activity）形成鲜明对比。然而，这种极光活动的驱动机制尚不明确。该极光的潜在驱动机制包括：与磁层等离子体盘（magnetospheric plasma disk）共转的破裂，或是恒星与伴星行星（companion planet）之间的亚阿尔文相互作用（sub-Alfvénic interaction）。后一种机制的预期特征包括：射电脉冲周期与恒星自转周期（stellar rotation period）的微小偏差，或是脉冲射电辐射在行星轨道周期（planetary orbital period）上的调制。为检测这些特征，我们需要对射电脉冲进行长期、宽带监测。在本提案中，我们旨在通过测量四个时间间隔为数日至数周的观测时段（epochs）内的脉冲到达时间，精确测定UV Ceti的脉冲自转周期。这将为未来长期监测中探测极光驱动机制（auroral engine）的特征奠定重要基础。若取得成功，本项目或将成为揭示这颗基准M型矮星（benchmark M-dwarf）中恒星-行星相互作用（star-planet interaction）特征的第一步。