A fresh idea to approach solar nebular condensation model

摘要

The condensation can include two processes: gas-solid and gas-liquid-soh'd condensations, Because nebular condensation occurred with temperature descending slowly, the forms of solar nebular condensation is dependent on the relationship between the pressure of nebular and 'triple point' of nebular matter. Based on vapor-condensation experiments of main silicate minerals in chondrites, Kushiro indicated that the pressure range of 'triple point' of nebular matter is about 10~(-1)—10~(-1) bar. Lewis estimated that pressure of solar nebula from the mercury region to the asteroid region is from 10~(-1) to 10~(-4) bar. It is seen from fig. 1 that the pressure range of nebula in terrestrial planet region and that of 'triple point' of nebular matter overlapped. If the estimated value is regarded as average value of nebular pressure, the pressure of nebula near the equator of nebular disk could be higher than the above value, so three types of condensation could occur in various planes of nebular disk forthe terrestrial planet and the asteroid region: the gas-liquid-solid condensation, gas-solid condensation, gas-liquid-solid and gas-solid combined condensation.