Disk-Outflow Models as Applied to High Mass Star Forming Regions through Methanol and Water Maser Observations  

作　　者：Hontas F. Farmer 

机构地区：[1]Department of Physical Science Richard J. Daley College, City Colleges of Chicago, Chicago, IL, USA

出　　处：《International Journal of Astronomy and Astrophysics》2014年第4期571-597,共27页天文学与天体物理学国际期刊（英文）

摘　　要：As the recent publication by Breen et al. (2013) found, Class II methanol masers are exclusively associated with high mass star forming regions. Based on the positions of the Class I and II methanol and H2O masers, UC H II regions and 4.5 μm infrared sources, and the center velocities (vLSR) of the Class I methanol and H2O masers, compared to the vLSR of the Class II methanol masers, we propose three disk-outflow models that may be traced by methanol masers. In all three models, we have located the Class II methanol maser near the protostar, and the Class I methanol maser in the outflow, as is known from observations during the last twenty years. In our first model, the H2O masers trace the linear extent of the outflow. In our second model, the H2O masers are located in a circumstellar disk. In our third model, the H2O masers are located in one or more outflows near the terminating shock where the outflow impacts the ambient interstellar medium. Together, these models reiterate the utility of coordinated high angular resolution observations of high mass star forming regions in maser lines and associated star formation tracers.As the recent publication by Breen et al. (2013) found, Class II methanol masers are exclusively associated with high mass star forming regions. Based on the positions of the Class I and II methanol and H2O masers, UC H II regions and 4.5 μm infrared sources, and the center velocities (vLSR) of the Class I methanol and H2O masers, compared to the vLSR of the Class II methanol masers, we propose three disk-outflow models that may be traced by methanol masers. In all three models, we have located the Class II methanol maser near the protostar, and the Class I methanol maser in the outflow, as is known from observations during the last twenty years. In our first model, the H2O masers trace the linear extent of the outflow. In our second model, the H2O masers are located in a circumstellar disk. In our third model, the H2O masers are located in one or more outflows near the terminating shock where the outflow impacts the ambient interstellar medium. Together, these models reiterate the utility of coordinated high angular resolution observations of high mass star forming regions in maser lines and associated star formation tracers.

关 键 词：MASERS METHANOL Massive STAR Formation Stars: Evolution Stars: DISTANCES 

分 类 号：P1[天文地球—天文学]