Evidence of Evolution in the Dense Cores in Massive Star Forming Regions
Evidence of Evolution in the Dense Cores in Massive Star Forming Regions作者机构:National Astronomical Observatories/Urumqi observatory Chinese Academy of SciencesUrumqi 830011 Graduate School of the Chinese Academy of Science Beijing 100080 Qinghai Station of Purple mountain Observatory Chinese Academy of Science DelinghaQinghai 817000
出 版 物:《Chinese Journal of Astronomy and Astrophysics》 (中国天文和天体物理学报(英文版))
年 卷 期:2005年第5卷第4期
页 面:363-370页
核心收录:
学科分类:07[理学] 070401[理学-天体物理] 0704[理学-天文学]
基 金:Supported by the National Natural Science Foundation of China
主 题:ISM: molecules masers radio lines: ISM stars: formation
摘 要:The excitation of H2O masers usually needs very high density gas,hence it can serve as a marker of dense gas in HⅡ region. We selected a sample of H2O maser sources from Plume et al. (four with, and four without detected CS(J = 7 - 6) emission), and observed them in ^13CO(J=1-0) and C^18O (J=1-0). C^18O (J=1-0) emission was detected only in three of the sources with detected CS(J=7-6) emission. An analysis combined with some data in the literature suggests that these dense cores may be located at different evolutionary stages. Multi-line observation study may provide us clues on the evolution of massive star forming regions and the massive stars themselves.