THE EXTREMELY LOW ACTIVITY COMET 209P/LINEAR DURING ITS EXTRAORDINARY CLOSE APPROACH IN 2014
THE EXTREMELY LOW ACTIVITY COMET 209P/LINEAR DURING ITS EXTRAORDINARY CLOSE APPROACH IN 2014
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2014 年非凡近距离接近期间活动极低的彗星 209P/线性
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
M. Knight
中科院分区：
文献类型：
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作者：
D. Schleicher;M. Knight
我们介绍了我们在2014年5月期间对209P/LINEAR彗星进行的观测活动的结果，这是两个世纪以来第三小的近地点彗星。在这种情况下，我们可以对这一微弱的天体进行几项研究，包括测量气体和尘埃的产生率，搜索彗发形态，以及直接探测原子核以测量其性质。事实上，我们成功地测量了一颗完整彗星35年来的最低产水率，以及相应的最小活动区域，∼0.007平方公里。结合雷达发现的彗核大小，这也是所有彗星中活性成分最小的，∼为0.024%。总而言之，这强烈地表明209P/LINEAR正在成为一个惰性天体。探测到了原子核，但由于看到了变化和空间尺度的变化，很难从内部彗星中解脱出来。即便如此，我们还是能够测量出与赫根罗瑟发现的两个可行的自转周期中较短的一个相一致的双峰光曲线。尘埃彗发的径向轮廓相当陡峭，类似于在其他一些非常贫乏的彗星上观察到的，这表明存在蒸发的冰粒。
We present results from our observing campaign of Comet 209P/LINEAR during its exceptionally close approach to Earth during 2014 May, the third smallest perigee of any comet in two centuries. These circumstances permitted us to pursue several studies of this intrinsically faint object, including measurements of gas and dust production rates, searching for coma morphology, and direct detection of the nucleus to measure its properties. Indeed, we successfully measured the lowest water production rates of an intact comet in over 35 years and a corresponding smallest active area, ∼0.007 km2. When combined with the nucleus size found from radar, this also yields the smallest active fraction for any comet, ∼0.024%. In all, this strongly suggests that 209P/LINEAR is on its way to becoming an inert object. The nucleus was detected but could not easily be disentangled from the inner coma due to seeing variations and changing spatial scales. Even so, we were able to measure a double-peaked lightcurve consistent with the shorter of two viable rotational periods found by Hergenrother. Radial profiles of the dust coma are quite steep, similar to that observed for some other very anemic comets, and suggest that vaporizing icy grains are present.