Volatile molecules in the formation of stars and planetary systems: abundances, isotopes and gas/ice ratios

2016 Fiscal Year Final Research Report

• Project/Area Number: 23540266
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Astronomy
• Research Institution: University of Tsukuba (2015-2016); Kobe University (2011-2014)
• Principal Investigator: Aikawa Yuri 筑波大学, 計算科学研究センター, 教授 (40324909)
• Project Period (FY): 2011-04-28 – 2017-03-31
• Keywords: 星間化学 / 星形成 / 原始惑星系円盤

Outline of Final Research Achievements

We studied the evolution of interstellar matter in the star- and planetary system-formation, focusing on (1) enhancement and reset of isotope ratios, (2) shock chemistry at the disk formation, and (3) chemistry around the snow lines in protoplanetary disks. On the first topic, we succeeded in constructing a comprehensive model on the evolution of molecular D/H ratio (especially water) from molecular cloud formation to protoplanetary disks. Secondary, we evaluated the critical velocity of colliding flows for the ice desorption as a function of gas density. On the third topic, we performed numerical calculations of molecular evolution in disks, and obtained analytical formulas of abundances of major ion molecules, including N2H+, which is considered to be a tracer of CO snow line. We also investigated the variation of elemental abundances (e.g. C/O ratio) caused by the gas-dust decoupling around the snow line; it is summarized as a student's Master thesis work, but needs further studies.

Free Research Field

理論天文学