论文标题
爆发准希尔达小行星P/2010 H2（VALES）
Outbursting Quasi-Hilda Asteroid P/2010 H2 (Vales)
论文作者
论文摘要
准希尔达小行星P/2010 H2（阀）在2010年进行了7.5个幅度爆发（1000倍）。在这里，我们在4月20日至8月10日的四个月内对这一事件进行了光学观察。从2010年4月20日至8月10日。 kg，大约是细胞核质量的1e-4，被视为半径为1.5 km的球体，密度为500 kg/m3。虽然爆发的上升阶段非常陡峭（亮度增加了小时的亮度），但随后褪色的发生缓慢（衰落的时间尺度在数周到几个月内增加），因为大的低速粒子从核中流出。褪色灯曲线的一个简单模型表明，从微米到厘米的弹出粒子占据了各种尺寸的范围，并遵循具有指数3.6 +/- 0.1（类似于其他彗星）的差分幂律分布。最快的颗粒的速度为210 m/s，表明与流量偶联的小晶粒的气拖加速度。已知可导致活跃小行星质量损失的低能过程，包括旋转破坏，热和干燥应力破裂以及静电排斥，无法产生以P/Vales测量的高颗粒速度，并且被打折。鉴于准希尔达斯的短动力学寿命和这些对象的低碰撞概率，影响起源不太可能。喷射的特定能量估计为220 j/kg。爆发在上个世纪与木星发生了一系列相遇，这与埋藏的超级载体的延迟激活（和/或地下无形无形冰的结晶）通过进行热量后进行热量。还考虑了雪崩产生的碎屑云中的潜在起源。
Quasi-Hilda asteroid P/2010 H2 (Vales) underwent a spectacular photometric outburst by 7.5 magnitudes (factor of 1000) in 2010. Here, we present our optical observations of this event in the four month period from April 20 to August 10. The outburst, starting UT 2010 April 15.76, released dust particles of total cross-section 17,600 sq km (albedo 0.1 assumed) and mass 1.2e9 kg, this being about 1e-4 of the mass of the nucleus, taken as a sphere of radius 1.5 km and density 500 kg/m3. While the rising phase of the outburst was very steep (brightness doubling time of hours), subsequent fading occurred slowly (fading timescales increasing from weeks to months), as large, low velocity particles drifted away from the nucleus. A simple model of the fading lightcurve indicates that the ejected particles occupied a broad range of sizes, from microns to centimeters, and followed a differential power-law distribution with index 3.6+/-0.1 (similar to that in other comets). The fastest particles had speeds 210 m/s, indicating gas-drag acceleration of small grains well-coupled to the flow. Low energy processes known to drive mass loss in active asteroids, including rotational disruption, thermal and desiccation stress cracking, and electrostatic repulsion, cannot generate the high particles speeds measured in P/Vales, and are discounted. Impact origin is unlikely given the short dynamical lifetimes of the quasi-Hildas and the low collision probabilities of these objects. The specific energy of the ejecta is estimated at 220 J/kg. The outburst follows a series of encounters with Jupiter in the previous century, consistent with the delayed activation of buried supervolatiles (and/or the crystallization of sub-surface amorphous ice) by conducted heat following an inward displacement of the perihelion. A potential origin in the debris cloud produced by avalanche is also considered.
