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천문우주과학 연구동향

천문우주과학과 관련된 국내외 상위 학술논문 및 특허 정보를 제공해 드립니다.

타이탄의 모래언덕 형성을 예측하기 위한 새로운 가설

Higher-than-predicted saltation threshold wind speeds on Titan
  • 작성자 : KASI
  • 작성일 : 2015-01-07
  • 조회수 : 2868
  • 저자evon M. Burr, Nathan T. Bridges et al,.
  • Absract


    Titan, the largest satellite of Saturn, exhibits extensive aeolian, that is, wind-formed, dunes, features previously identified exclusively on Earth, Mars and Venus.Wind tunnel data collected under ambient and planetary-analogue conditions inform our models of aeolian processes on the terrestrial planets.However, the accuracy of these widely used formulations in predicting the threshold wind speeds required tomove sand by saltation, or by short bounces, has not been testedunder conditions relevant for non-terrestrial planets. Here we derive saltation threshold wind speeds under the thick-atmosphere, low-gravity and low-sediment-density conditions on Titan, using a high-pressure wind tunnel refurbished to simulate the appropriate kinematic viscosity for the near-surface atmosphere of Titan. The experimentally derived saltation threshold wind speeds are higher than those predicted by models based on terrestrial-analogue experiments, indicating the limitations of thesemodels for such extreme conditions. The models can be reconciled with the experimental resultsby inclusion of the extremely lowratio of particle density to fluid density on Titan. Whereas the density ratio term enables accurate modelling of aeolian entrainment in thick atmospheres, such as those inferred for some extrasolar planets, our results also indicate that for environments with high density ratios, such as in jets on icy satellites or in tenuous atmospheres or exospheres, the correction for lowdensity-ratio conditions is not required.


  • 게재정보NATURE(2014.12.08)에 게재된 논문임
  • 첨부파일
  • 원 문http://www.nature.com/nature/journal/v517/n7532/pdf/nature14088.pdf
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