垂死的恒星发出的光可以粉碎小行星
垂死的恒星发出的光可以粉碎小行星
Even stars that don’t end their lives in supernovae can spell catastrophe for the smallest members of their solar system. New research suggests that the light of dying stars is enough to pulverize asteroids located hundreds of times further than the Earth-Sun distance from their star.
即使是那些没有在超新星中结束生命的恒星也会给太阳系中最小的成员带来灾难。新的研究表明，濒死恒星发出的光足以粉碎距离其恒星数百倍于地球-太阳距离的小行星。
The study, published in the Monthly Notices of the Royal Astronomical Society, looked at the consequence of the YORP effect in stellar systems. Named after the four scientists that contributed to the idea (Yarkovsky, O'Keefe, Radzievskii, and Paddack), the YORP effect is when an asteroid spins itself to death due to stellar radiation.
这项研究发表在《皇家天文学会月刊》上，研究了约普效应对恒星系统的影响。“约普效应”是以四位科学家的名字命名的，这四位科学家分别是:雅科夫斯基、奥基夫、拉济耶夫斯基和帕达克。
Alfredo Carpineti
Starlight has a small but not zero momentum. As we have seen with the successful solar sail tests in the last decade or so, photons from the Sun can push objects around. When starlight hits an asteroid, it is absorbed, redistributed internally, and then reemitted at a different location.
星光有一个小但不是零的动量。正如我们在过去十年左右成功的太阳帆试验中所看到的，来自太阳的光子可以推动物体。当星光撞击小行星时，它被吸收，在内部重新分布，然后在不同的位置重新发射。
Asteroids are large piles of space rocks that often remain together due to weak gravity; however, they are not well mixed, so the heating from stellar radiation and the subsequent emissions are not balanced. This imbalance in the emissions produces a small torque. Over time and with the star getting brighter and brighter, the torque increases. Since the gravity exerted on the asteroids is too weak to counterbalance the forces pulling the asteroids apart, the space rocks become dust.
小行星是一大堆太空岩石，由于重力较弱，它们通常会保持在一起;然而，它们并没有很好地混合在一起，因此恒星辐射产生的热量和随后的辐射并不平衡。这种排放的不平衡产生了一个小扭矩。随着时间的推移，恒星变得越来越亮，扭矩也随之增大。由于施加在小行星上的引力太弱，无法抵消把小行星拉开的力，太空岩石就变成了尘埃。
“When a typical star reaches the giant branch stage, its luminosity reaches a maximum of between 1,000 and 10,000 times the luminosity of our Sun. Then the star contracts down into an Earth-sized white dwarf very quickly, where its luminosity drops to levels below our Sun’s. Hence, the YORP effect is very important during the giant branch phase, but almost non-existent after the star has become a white dwarf,” lead author Dr Dimitri Veras, from the University of Warwick’s Astronomy and Astrophysics Group, said in a statement.
“当一颗典型的恒星达到大分支阶段时，它的光度最大达到太阳光度的1000到10000倍。然后这颗恒星迅速收缩成地球大小的白矮星，其光度下降到低于太阳的亮度。因此，约普效应在大分支阶段非常重要，但在恒星变成白矮星后几乎不存在。华威大学天文和天体物理小组的首席作者迪米特里·维拉斯博士在一份声明中说。
The work provides insight into the future of our Solar System. In about 6 billion years, our Sun will have run out of fuel, shedding its outer layers and collapsing into a white dwarf. This will mean bye to the asteroid belt in record time.
这项工作为我们了解太阳系的未来提供了视角。在大约60亿年后，我们的太阳将耗尽燃料，脱离它的外层，坍缩成一颗白矮星。这意味着小行星带将在创纪录的时间内消失。
“For one solar-mass giant branch stars – like what our Sun will become – even exo-asteroid belt analogues will be effectively destroyed. The YORP effect in these systems is very violent and acts quickly, on the order of a million years. Not only will our own asteroid belt be destroyed, but it will be done quickly and violently. And due solely to the light from our Sun," said Dr Veras.
“对于一个太阳质量的巨型分支恒星——就像我们的太阳将会变成的样子——即使是外小行星带的类似物也会被有效地摧毁。约珥普效应在这些系统中非常强烈，而且作用迅速，大约有一百万年的时间。我们自己的小行星带不仅会被摧毁，而且会被迅速而猛烈地摧毁。而这仅仅是由于来自太阳的光。”维拉斯博士说。
The simulations suggest that the size of the debris will plateau when objects are less than 100 meters (330 feet) across, as these often have quite high internal strength. The researchers think that by studying emissions from the asteroid debris around white dwarfs, it might be possible to gain insight into what the stellar system used to be like before the star died.
模拟表明，当物体直径小于100米(330英尺)时，碎片的大小将趋于平稳，因为这些物体通常具有相当高的内部强度。研究人员认为，通过研究白矮星周围小行星碎片的排放，有可能了解恒星死亡前的恒星系统。
