OBSERVATIONS OF 1999 YC AND THE BREAKUP OF THE GEMINID STREAM PARENT
OBSERVATIONS OF 1999 YC AND THE BREAKUP OF THE GEMINID STREAM PARENT
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DOI：
10.1088/0004-6256/136/2/881
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发表时间：
2008-05
期刊：
影响因子：
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通讯作者：
T. Kasuga;D. Jewitt
中科院分区：
文献类型：
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作者：
T. Kasuga;D. Jewitt
阿波罗小行星1999 YC可能与法厄同-双子座星流复合体（Phaethon-Geminid Stream Complex，PGC）有着共同的动力学联系（Ohtsuka et al.）。在这里，我们提出了光度观测，以确定1999年YC的物理性质。该天体的反射光谱接近中性，与相关天体3200法厄同和2005 UD相似，但略偏红。假设一个半径等于3200法厄同的半径，我们发现它的直径是1.4 ± 0.1公里。时间分辨宽带测光产生的双峰旋转周期为4.4950 ± 0.0010 h，而光变曲线的范围显示出一个细长的形状，投影轴比为1.9。表面亮度模型没有提供证据证明存在着短周期活跃彗星核的那种持续的质量损失。质量损失的上限设定为10 - 3 kg s-1，对应于表面升华水冰的比例上限<10 - 3。如果双子座星系流持续超过1000年的年龄，1999 YC的总质量损失（3 × 107公斤）与报告的星系流质量（1012-1013公斤）相比将是很小的，这表明该星系流是母天体灾难性分裂的产物，而不是稳定状态的分裂。
The Apollo asteroid 1999 YC may share a dynamical association with the Phaethon–Geminid Stream Complex (PGC) (Ohtsuka et al. ). Here, we present photometric observations taken to determine the physical properties of 1999 YC. The object shows a nearly neutral reflection spectrum, similar to but slightly redder than the related objects 3200 Phaethon and 2005 UD. Assuming an albedo equal to that of 3200 Phaethon, we find that the diameter is 1.4 ± 0.1 km. Time-resolved broadband photometry yields a double-peaked rotational period of 4.4950 ± 0.0010 h, while the range of the light curve indicates an elongated shape having a projected axis ratio of ∼1.9. Surface brightness models provide no evidence of lasting mass loss of the kind seen in active short-period cometary nuclei. An upper limit to the mass loss is set at ∼10−3 kg s−1, corresponding to an upper limit on the fraction of the surface that could be sublimating water ice of <10−3. If sustained over the 1000 yr age of the Geminid stream, the total mass loss from 1999 YC (3 × 107 kg) would be small compared to the reported stream mass (∼1012–1013 kg), suggesting that the stream is the product of catastrophic, rather than steady-state, breakup of the parent object.