12 GHz methanol maser outflow from the massive star-forming region: G35.20-0.74  

作　　者：Qing-Zeng Yan Bo Zhang Zheng-Hong Tang Xing-Wu Zheng 

机构地区：[1]Shanghai Astronomical Observatory,Chinese Academy of Sciences [2]Max-Plank-Institut für Radioastronomie,Auf dem Hügel 69,53121 Bonn,Germany [3]School of Astronomy and Space Science, Nanjing University

出　　处：《Research in Astronomy and Astrophysics》2013年第7期815-826,共12页天文和天体物理学研究（英文版）

基　　金：supported by the National Science Foundation of China (Grant Nos.11073046 and 11133008)

摘　　要：We report the internal proper motions of 12 GHz methanol masers in mas-sive star-forming region G35.20-0.74 observed with the Very Long Baseline Array （VLBA） at four epochs spanning about 1.5 yr. Two groups of maser features were de-tected, groups A and B, and the latter that had a V-shaped spatial distribution is likely tracing the north outflow in G35.20-0.74. We present a three-dimensional model for the kinematics of these masers, by assuming the interstellar medium was blown by the stellar wind from the driving source （G35.2N） of the outflow. Adopting a position angle of ～ 81° for the main axis of the outflow from previous studies, we estimate an inclination of 35 ° ± 5.5°, a velocity of 8.1 ± 0.7 km s^-1 for the stellar wind along the main axis and an expansion speed gradient of 0.05 ± 0.016 km s^-1 AU^-1. From the model, we derive the age of the north outflow in G35.20-0.74 to be ～ 1.6 × 10^4 yr.We report the internal proper motions of 12 GHz methanol masers in mas-sive star-forming region G35.20-0.74 observed with the Very Long Baseline Array （VLBA） at four epochs spanning about 1.5 yr. Two groups of maser features were de-tected, groups A and B, and the latter that had a V-shaped spatial distribution is likely tracing the north outflow in G35.20-0.74. We present a three-dimensional model for the kinematics of these masers, by assuming the interstellar medium was blown by the stellar wind from the driving source （G35.2N） of the outflow. Adopting a position angle of ～ 81° for the main axis of the outflow from previous studies, we estimate an inclination of 35 ° ± 5.5°, a velocity of 8.1 ± 0.7 km s^-1 for the stellar wind along the main axis and an expansion speed gradient of 0.05 ± 0.016 km s^-1 AU^-1. From the model, we derive the age of the north outflow in G35.20-0.74 to be ～ 1.6 × 10^4 yr.

关 键 词：masers - ISM： molecules - stars： kinematics - stars： individual（G35.20-0.74） - stars： winds OUTFLOWS 

分 类 号：P144[天文地球—天体物理]