PHYSICAL PROPERTIES OF MAIN-BELT COMET P/2005 U1 (READ)
PHYSICAL PROPERTIES OF MAIN-BELT COMET P/2005 U1 (READ)
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DOI：
10.1088/0004-6256/137/1/157
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发表时间：
2009-01-01
影响因子：
5.3
通讯作者：
Ishiguro, Masateru
中科院分区：
文献类型：
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作者：
Hsieh, Henry H.;Jewitt, David;Ishiguro, Masateru
主带彗星动态地占据主小行星带中的小行星轨道。在这里，我们展示了对该彗星群中第二个已知成员 P/2005 U1 (Read) 的物理观测，该彗星在 2005 年 10 月 24 日至 2005 年 12 月 27 日期间显示出剧烈的彗星活动。对 P/Read 尘埃发射的蒙特卡罗数值模拟表明，慧发和彗尾在光学上主要由尺寸大于 10 μm 的尘埃颗粒主导，最终喷射速度为 0.2-3 m s(-1)。我们估计 P/Read 在此期间的质量损失率约为 0.2 kg s(-1)，大约比 133P/Elst-Pizarro 计算的质量损失率大一个数量级。我们还发现，排放可能在 P/Read 发现之前至少 2 个月开始，尽管我们注意到这是一个下限，而且更早的开始时间也是可能的。 P/Read 处于活动状态时测得的光学颜色大约为太阳色（B - V = 0.63 +/- 0.05，V - R = 0.37 +/- 0.04，R - I = 0.39 +/- 0.04），但可能主要由慧差粒子主导。 2007 年对 P/Read 的观测显示，当它基本上不活跃时，它显示出一个极小的核，其绝对星等 H-R 类似于 20.1 +/- 0.4，对应于有效半径 r(e) 类似于 0.3 公里。 P/Read 的活动与升华驱动的粉尘排放一致，与撞击引起的粉尘排放不一致，尽管 2005 年爆发的异常强度表明它可能是由于新暴露的挥发性物质库的升华所致。
The main-belt comets occupy dynamically asteroidal orbits in the main asteroid belt. Here we present physical observations of the second-known member of this population, P/2005 U1 (Read), which showed vigorous cometary activity from 2005 October 24 to 2005 December 27. Monte Carlo numerical simulations of P/Read's dust emission indicate that the coma and tail are optically dominated by dust particles larger than 10 mu m in size with terminal ejection velocities of 0.2-3 m s(-1). We estimate P/Read's mass-loss rate during this period to be approximately 0.2 kg s(-1), roughly an order of magnitude larger than that calculated for 133P/Elst-Pizarro. We also find that emission likely began at least 2 months prior to P/Read's discovery, though we note this is a lower limit and that earlier start times are possible. Optical colors measured for P/Read while it was active are approximately solar (B - V = 0.63 +/- 0.05, V - R = 0.37 +/- 0.04, R - I = 0.39 +/- 0.04) but are likely to be dominated by coma particles. Observations of P/Read in 2007 when it appears largely inactive show an extremely small nucleus with an absolute magnitude of H-R similar to 20.1 +/- 0.4, corresponding to an effective radius of r(e) similar to 0.3 km. P/Read's activity is consistent with sublimation-driven dust emission and inconsistent with dust emission due to an impact, though the unusual strength of the 2005 outburst suggests the possibility that it could have been due to the sublimation of a freshly exposed reservoir of volatile material.