SIMULTANEOUS MULTIWAVELENGTH OBSERVATIONS OF MAGNETIC ACTIVITY IN ULTRACOOL DWARFS. IV. THE ACTIVE, YOUNG BINARY NLTT 33370 AB (= 2MASS J13142039+1320011)
SIMULTANEOUS MULTIWAVELENGTH OBSERVATIONS OF MAGNETIC ACTIVITY IN ULTRACOOL DWARFS. IV. THE ACTIVE, YOUNG BINARY NLTT 33370 AB (= 2MASS J13142039+1320011)
复制标题
超冷矮星磁活动的同时多波长观测。
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
David Charbonneau
中科院分区：
文献类型：
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作者：
Peter K. G. Williams;E. Berger;Jonathan Irwin;Z. Berta;David Charbonneau
我们介绍了对活动的、年轻的、低质量的双星NLTT 33370 AB(混合谱型M7e)的多历元同时射电、光学、Hα、UV和X射线观测。这个系统以其极端的磁活动水平而引人注目：它是已知的射电亮度最高的超冷矮星(UCD)，这里我们展示了它也是已知的最X射线发光的超冷矮星之一。我们在所有波段都探测到了该系统，并发现了耀斑和周期变化的复杂现象。对光学曲线的分析表明，两个周期同时存在，3.7859 ± 0.0001和3.7130 ± 0.0002小时。虽然这两个信号的差异只有∼2%，但对UCD机制中的差异旋转的研究表明，它不能对这两个信号负责。该系统的射电发射至少由三个部分组成：快速100%极化耀斑、与光学发射周期性同相调制的明亮发射，以及仅在2013年观测活动中出现的另外一个周期部分。我们将最后一个解释为回旋同步加速器特征，它与大尺度磁场和冷的赤道等离子体环有关。然而，在所有自转阶段持续的快速耀斑意味着小规模磁环也存在，并且几乎连续地重新连接。给出了混合体系在9个数量级以上波长上的光谱能量分布。NLTT 33370 AB中存在的显著磁性将影响其基本参数，组件的半径和温度可能分别改变∼+20%和∼−10%。最后，我们建议空间分辨的观测可以澄清这个系统的许多方面的性质。
We present multi-epoch simultaneous radio, optical, Hα, UV, and X-ray observations of the active, young, low-mass binary NLTT 33370 AB (blended spectral type M7e). This system is remarkable for its extreme levels of magnetic activity: it is the most radio-luminous ultracool dwarf (UCD) known, and here we show that it is also one of the most X-ray luminous UCDs known. We detect the system in all bands and find a complex phenomenology of both flaring and periodic variability. Analysis of the optical light curve reveals the simultaneous presence of two periodicities, 3.7859 ± 0.0001 and 3.7130 ± 0.0002 hr. While these differ by only ∼2%, studies of differential rotation in the UCD regime suggest that it cannot be responsible for the two signals. The system's radio emission consists of at least three components: rapid 100% polarized flares, bright emission modulating periodically in phase with the optical emission, and an additional periodic component that appears only in the 2013 observational campaign. We interpret the last of these as a gyrosynchrotron feature associated with large-scale magnetic fields and a cool, equatorial plasma torus. However, the persistent rapid flares at all rotational phases imply that small-scale magnetic loops are also present and reconnect nearly continuously. We present a spectral energy distribution of the blended system spanning more than 9 orders of magnitude in wavelength. The significant magnetism present in NLTT 33370 AB will affect its fundamental parameters, with the components' radii and temperatures potentially altered by ∼+20% and ∼−10%, respectively. Finally, we suggest spatially resolved observations that could clarify many aspects of this system's nature.
系外行星凌日变率：HD 189733b 周围的弓形冲击和风
影响因子：
4.8
作者：
Llama J
通讯作者：
Llama J
影响因子：
6.5
作者：
T. Reinhold;A. Reiners;G. Basri
通讯作者：
T. Reinhold;A. Reiners;G. Basri