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지구 인근 소행성 가운데 낮은 알베도 소행성이 극히 드문 이유

Super-catastrophic disruption of asteroids at small perihelion distances
  • 작성자 : KASI
  • 작성일 : 2016-02-18
  • 조회수 : 2222
  • 저자Mikael Granvik, Alessandro Morbidelli et al.,
  • Absract

     

     

    Most near-Earth obj*cts came from the asteroid belt and drifted via non-gravitational thermal forces into resonant escape routes that, in turn, pushed them onto planet-crossing orbits1–3. Models predict that numerous asteroids should be found on orbits that closely approach the Sun, but few have been seen. In addition, even though the near-Earth-obj*ct population in general is an even mix of low-albedo (less than ten per cent of incident radiation is reflected) and high-albedo (more than ten per cent of incident radiation is reflected) asteroids, the characterized asteroids near the Sun typically have high albedos4. Here we report a quantitative comparison of actual asteroid detections and a near-Earth-obj*ct model (which accounts for observational selection effects). We conclude that the deficit of low-albedo obj*cts near the Sun arises from the super-catastrophic breakup (that is, almost complete disintegration) of a substantial fraction of asteroids when they achieve perihelion distances of a few tens of solar radii. The distance at which destruction occurs is greater for smaller asteroids, and their temperatures during perihelion passages are too low for evaporation to explain their disappearance. Although both bright and dark (high- and low-albedo) asteroids eventually break up, we find that low-albedo asteroids are more likely to be destroyed farther from the Sun, which explains the apparent excess of high-albedo near-Earth obj*cts and suggests that low-albedo asteroids break up more easily as a result of thermal effects.

     


  • 게재정보NATURE(2016.02.18.)에 게재된 논문임
  • 첨부파일
  • 원 문http://www.nature.com/nature/journal/v530/n7590/pdf/nature16934.pdf
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