发表机构
Universitat de València; Centro de Astrobiología, CSIC-INTA; Lowell Observatory; Trinity College Dublin, The University of Dublin; University of Colorado Boulder; American Museum of Natural History（瓦伦西亚大学; 西班牙国家研究委员会-国家航空航天技术研究所天体生物学中心; 洛厄尔天文台; 都柏林大学圣三一学院; 科罗拉多大学博尔德分校; 美国自然历史博物馆）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过多波段观测和极光建模，发现L3.5矮星LSPM J0036+1821的射电辐射呈现类木星极光特征，由电子回旋脉泽不稳定性驱动，并确定了其精确自转周期。
AI 中文摘要
超冷矮星表现出射电辐射，揭示了强磁场和复杂的磁层过程。它们的极光辐射类似于在磁化的太阳系行星上观测到的现象，为研究其磁场拓扑结构提供了框架。我们旨在通过多波段分析来表征L3.5矮星LSPM J0036+1821的磁活动、自转和大气变率。我们开展了一项长期监测活动，结合了甚大阵列和甚长基线干涉测量阵列的射电观测以及TESS光学测光，时间跨度从2019年到2023年。我们分析了时间序列数据以推导精确的自转周期，并构建了光变曲线和射电动态频谱。射电光变曲线使用类似于木星磁层的极光框架进行建模，该框架包含主椭圆和活跃场线分量。我们探测到持续、紧凑的射电辐射，具有显著的变率和高的圆偏振度。周期图分析从射电数据得出自转周期为3.07941±0.00020小时，与TESS光学周期（3.07908±0.00038小时）一致。射电光变曲线显示出稳定的形态，其特征为非对称、受自转调制的脉冲。我们的建模使用混合极光情景再现了该辐射，其中主椭圆贡献一个稳定分量，而活跃场线产生主导的、可变的爆发。短期变率可通过发射锥几何结构或活跃场线经度的小变化来解释。LSPM J0036+1821的射电辐射与由电子回旋脉泽不稳定性在结构化磁层中驱动的极光过程一致。其行为与类木星极光系统一致，可能涉及类似于太阳系中观测到的伴星驱动或内部驱动的磁层相互作用。
英文摘要
Ultracool dwarfs exhibit radio emission revealing strong magnetic fields and complex magnetospheric processes. Their auroral emission resembles that observed in magnetized Solar System planets, providing a framework to investigate their magnetic topology. We aim to characterize the magnetic activity, rotation, and atmospheric variability of the L3.5 dwarf LSPM J0036+1821 through a multiwavelength analysis. We conducted a long-term monitoring campaign combining radio observations from the Very Large Array and very long baseline interferometry arrays with TESS optical photometry, spanning 2019-2023. We analyzed time-series data to derive precise rotation periods and constructed light curves and radio dynamic spectra. The radio lightcurves were modeled using an auroral framework analogous to Jupiter's magnetosphere, incorporating main oval and active field line components. We detect persistent, compact radio emission with significant variability and high circular polarization. Periodogram analysis yields a rotation period of 3.07941 $\pm$ 0.00020h from radio data, consistent with the TESS optical period (3.07908 $\pm$ 0.00038h). The radio light curves display stable morphology characterized by asymmetric, rotationally modulated pulses. Our modeling reproduces the emission using a hybrid auroral scenario, with the main oval contributing a stable component and an active field line producing dominant, variable bursts. Short-term variability is explained by small changes in emission cone geometry or longitude of the active field line. The radio emission of LSPM J0036+1821 is consistent with auroral processes driven by the electron cyclotron maser instability in a structured magnetosphere. The behavior is consistent with a Jupiter-like auroral system, possibly involving companion-driven or internally-driven magnetospheric interactions analogous to those observed in the Solar System.
CommentsAccepted for publication in A&A
