Extreme collisions between planetesimals as the origin of warm dust around a Sun-like star
Extreme collisions between planetesimals as the origin of warm dust around a Sun-like star
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星子之间的极端碰撞是类太阳恒星周围温暖尘埃的起源
作者：
I. Song;B. Zuckerman;A. Weinberger;E. Becklin
太阳系中小行星之间缓慢但持续的碰撞产生了被称为黄道光的稀薄尘埃云（因为尘埃反射的光）。在年轻的太阳系中，这种碰撞更为常见，尘埃的产生率应该要大很多倍。然而，在比太阳年轻得多的恒星周围的黄道带区域，却很少发现大量尘埃。众所周知，尘埃围绕数百个主序恒星运行，但这种尘埃很冷，来自海王星轨道之外的柯伊伯带类似区域。尽管进行了多次搜索，但只有少数主序星发现了类似于地球附近黄道尘埃的温暖（> 120 K）尘埃。因此，与太阳系类地行星轨道相对应的恒星区域中行星形成的迹象（以天体之间碰撞的形式）一直难以捉摸。在这里，我们报告了太阳型恒星 BD+20 307（HIP 8920，SAO 75016）周围存在异常大量温暖的小型硅酸盐尘埃颗粒。尘埃的成分和数量可以用最近小行星或其他“星子”之间频繁或巨大的碰撞来解释，这些小行星或其他“星子”的轨道受到附近行星的扰动。
The slow but persistent collisions between asteroids in our Solar System generate a tenuous cloud of dust known as the zodiacal light (because of the light the dust reflects). In the young Solar System, such collisions were more common and the dust production rate should have been many times larger. Yet copious dust in the zodiacal region around stars much younger than the Sun has rarely been found. Dust is known to orbit around several hundred main-sequence stars, but this dust is cold and comes from a Kuiper-belt analogous region out beyond the orbit of Neptune. Despite many searches, only a few main-sequence stars reveal warm (> 120 K) dust analogous to zodiacal dust near the Earth. Signs of planet formation (in the form of collisions between bodies) in the regions of stars corresponding to the orbits of the terrestrial planets in our Solar System have therefore been elusive. Here we report an exceptionally large amount of warm, small, silicate dust particles around the solar-type star BD+20 307 (HIP 8920, SAO 75016). The composition and quantity of dust could be explained by recent frequent or huge collisions between asteroids or other ‘planetesimals’ whose orbits are being perturbed by a nearby planet.