Comet 240P/NEAT Is Stirring
Comet 240P/NEAT Is Stirring
复制标题
彗星 240P/NEAT 正在搅动
DOI：
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发表时间：
2019
影响因子：
4.9
通讯作者：
J. Zolkower
中科院分区：
文献类型：
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作者：
M. Kelley;D. Bodewits;Q. Ye;T. Farnham;E. Bellm;R. Dekany;D. Duev;G. Helou;T. Kupfer;R. Laher;F. Masci;T. Prince;B. Rusholme;D. Shupe;M. Soumagnac;J. Zolkower
彗星是在原行星盘中形成的原始天体，在太阳系的历史上基本上被保存了下来。然而，它们并不是原始的，彗核的表面确实会进化。为了了解它们原始性质的程度，我们必须定义影响它们表面和表面的机制。我们考察了240P/NEAT彗星在三个连续轨道上的光曲线，并考察了三个显著变亮的事件(Δm∼−2 MAG)。与典型的彗星爆发不同，这三个事件中的每一个都是长期存在的，活动增强至少持续3-6个月。兹维基瞬变设施观察到的第三次事件至少分两个阶段发生。这一反常行为似乎是在2007年彗星被木星扰动后开始的，将其近日点距离从2.53 Au减少到2.12 Au。我们认为，变亮事件是向更高基线活动水平的临时转变，这是由日照增加所带来的，这使得以前隔热的次表层变暖。新的活动被分离到核上的一个或两个位置，表明表面或直接的次表面是不均匀的。对这一现象的进一步研究可能会提供对彗星爆发、近地表核的结构和彗核地幔的洞察。
Comets are primitive objects that formed in the protoplanetary disk, and have been largely preserved over the history of the solar system. However, they are not pristine, and surfaces of cometary nuclei do evolve. In order to understand the extent of their primitive nature, we must define the mechanisms that affect their surfaces and comae. We examine the lightcurve of comet 240P/NEAT over three consecutive orbits, and investigate three events of significant brightening (Δm ∼ −2 mag). Unlike typical cometary outbursts, each of the three events are long-lived, with enhanced activity for at least 3–6 months. The third event, observed by the Zwicky Transient Facility, occurred in at least two stages. The anomalous behavior appears to have started after the comet was perturbed by Jupiter in 2007, reducing its perihelion distance from 2.53 to 2.12 au. We suggest that the brightening events are temporary transitions to a higher baseline activity level, brought on by the increased insolation, which has warmed previously insulated sub-surface layers. The new activity is isolated to one or two locations on the nucleus, indicating that the surface or immediate sub-surface is heterogeneous. Further study of this phenomenon may provide insight into cometary outbursts, the structure of the near-surface nucleus, and cometary nucleus mantling.
DOI：
10.1088/1538-3873/aaecbe
发表时间：
2019-01-01
影响因子：
3.5
作者：
Bellm, Eric C.;Kulkarni, Shrinivas R.;Zolkower, Jeffry
通讯作者：
Zolkower, Jeffry