The Contribution of Asteroids to the Primordial Terrestrial Ocean

• Main Authors: Dah-Lih You, 游大立
• Other Authors: Wing-Huen Ip
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/51360907796781625795

碩士 === 國立中央大學 === 天文研究所 === 91 === Direct integration method using the SWIFT RMVS3 (Regularized Mixed Variable Sympletic 3) code has been used to investigate the long-term (~ 100 Myr) orbital evolution of about 10 thousand test particles originally distributed in the asteroid belt. This is to provide statistical estimates of the collisional probabilities against surface impacts with Mars, Earth and Venus by strary bodies ejected from such intermediate source region of the Near-Earth asteroids. The major goal is to investigate the potential contributions to the primordial oceans of the terrestrial planets from the asteroidal objects. Our calculations suggest that Earth could in principle gained between one to a few tens of the present oceanic water from asteroidal impact. But the exact value depends sensitively on the assumption of the initial mass distribution in the solar nebula. When compared with the isotope ratios of D/H of the Standard Mean Oceanic Water (SMOW), the cometary water and primitive meteorites, it is concluded that asteroids should be a more important source of oceanic water than comets. But water contained in the Earth’s interior could also make significant contribution.