论文标题

$ε$ indi BA,BB系统中云覆盖范围的大规模变化

Large-scale changes of the cloud coverage in the $ε$ Indi Ba,Bb system

论文作者

Hitchcock, J. A., Helling, Ch., Scholz, A., Hodosan, G., Dominik, M., Hundertmark, M., Jørgensen, U. G., Longa-Peña, P., Sajadian, S., Skottfelt, J., Snodgrass, C., Bozza, V., Burgdorf, M. J., Campbell-White, J., Jaimes, Roberto Figuera, Fujii, Y. I., Haikala, L. K., Henning, T., Hinse, T. C., Lowry, S., Mancini, L., Rahvar, S., Rabus, M., Southworth, J., von Essen, C.

论文摘要

我们介绍了\ textit {i} -band光度监测的14晚的结果,附近的棕色矮人二进制,$ε$ indi ba,bb。在2个月内获取观察结果,并在通常的1.4分钟的较高节奏下总计接近42小时的覆盖范围。仅$ 0.7''$的间隔,我们不解决各个组件,因此有效地对待二进制组件,就好像它是一个对象一样。但是,$ε$ indi ba(光谱T1)是最明亮的已知T型棕色矮人,预计将主导光度信号。在每个观察的每个人的夜晚,我们通常都没有发现与目标相关的强大可变性,但是在活动的两个月内,平均亮度的显着变化(高达0.10美元)。在至少2天的时间表上,这种强烈的变化显而易见。我们没有检测到没有明确的周期性签名,这表明我们可能正在观察T1棕色矮人几乎是杆的,而平均亮度的长天变化是由云覆盖范围的大规模结构的变化引起的。动态云很可能会产生闪电,并获取互补的高节奏\ textit {v} -band和h \ textit {$α$}图像以搜索与随机“罢工”相关的发射签名。我们在这两个通带中均未报告目标的阳性检测。

We present the results of 14 nights of \textit{I}-band photometric monitoring of the nearby brown dwarf binary, $ε$ Indi Ba,Bb. Observations were acquired over 2 months, and total close to 42 hours of coverage at a typically high cadence of 1.4 minutes. At a separation of just $0.7''$, we do not resolve the individual components, and so effectively treat the binary as if it were a single object. However, $ε$ Indi Ba (spectral type T1) is the brightest known T-type brown dwarf, and is expected to dominate the photometric signal. We typically find no strong variability associated with the target during each individual night of observing, but see significant changes in mean brightness - by as much as $0.10$ magnitudes - over the 2 months of the campaign. This strong variation is apparent on a timescale of at least 2 days. We detect no clear periodic signature, which suggests we may be observing the T1 brown dwarf almost pole-on, and the days-long variability in mean brightness is caused by changes in the large-scale structure of the cloud coverage. Dynamic clouds will very likely produce lightning, and complementary high cadence \textit{V}-band and H\textit{$α$} images were acquired to search for the emission signatures associated with stochastic "strikes." We report no positive detections for the target in either of these passbands.

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