Near-infrared monitoring of Io and detection of a violent outburst on 29 August 2013
Near-infrared monitoring of Io and detection of a violent outburst on 29 August 2013
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DOI：
10.1016/j.icarus.2014.06.006
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发表时间：
2014-11
期刊：
影响因子：
3.2
通讯作者：
K. Kleer;I. Pater;A. Davies;M. Ádámkovics
中科院分区：
文献类型：
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作者：
K. Kleer;I. Pater;A. Davies;M. Ádámkovics
从2013年8月开始，我们使用Gemini N的3.8 μm自适应光学成像和NASA IRTF的2-5 μm圆盘集成光谱，对Io进行近红外监测。这些观测在2013-2014年期间进行，与ISAS/JAXA的EXCEED任务对木卫一等离子体环面的持续监测相一致，除了能够评估大规模爆发的频率和性质外，还将能够直接观察火山释放气体对环面的推测影响。2013年8月29日，我们探测到木卫一在西经223.5±2.6°，北纬29.1±1.8°发生了一次强大的喷发（编号为201308C）。这次喷发的辐射强度在15到250太瓦之间，是迄今为止在木卫一上观测到的最强烈的喷发之一，属于罕见的“爆发”类型。这是2013年8月在木卫一上看到的第三次这种类型的喷发，这是前所未有的。在随后的几天和几周内，热辐射衰减的图表也是前所未有的。对爆发谱的建模将喷发温度的下限设定在1200-1300 K之间，表明喷发温度应为1900 K或更高，通常与超镁铁性熔岩成分有关。这次喷发很可能是一次高能量、大容量的熔岩喷泉事件。
We present initial data from our campaign to monitor Io in the near-infrared, beginning in August 2013, using 3.8-μm adaptive optics imaging at Gemini N and 2–5 μm disk-integrated spectroscopy at NASA’s IRTF. Conducted during 2013–2014, these observations are coincident with the ISAS/JAXA EXCEED mission’s continuous monitoring of the Io plasma torus and will enable the speculated effects of volcanic outgassing on the torus to be observed directly, in addition to enabling an assessment of the frequency and properties of large-scale outbursts. On 29 August 2013 we detected a powerful eruption (designated 201308C) on Io at 223.5 ± 2.6°W, 29.1 ± 1.8°N. Emitting between 15 and >25 TW, this event is one of the most powerful eruptions ever seen on Io and falls into the rare “outburst” class. This was the third eruption of this type seen on Io in August 2013, an unprecedented occurrence. Also unprecedented was the charting of the decay in thermal emission over the subsequent days and weeks. Modeling of the outburst spectrum places a lower bound of 1200–1300 K on the eruption temperature, and is suggestive of temperatures 1900 K or higher, typically associated with ultramafic lava composition. The eruption is likely a highly energetic, high-volume lava fountain event.