Oral Presentation

Infrared photometric and spectroscopic properties of high-mass YSOs in M17

Author(s): Zhiwei Chen

Presenter: Zhiwei Chen (Purple Mountain Observatory)

We carried out infrared imaging and spectroscopic observations for the high-mass YSOs in the massive star-forming region M17. In this talk we present the results of several high-mass YSOs in M17. We reveal the circumstellar structures of these high-mass YSOs by the high-resolution infrared images, and find evidence of interaction between the expanding HII region and the high-mass YSOs lying close to the ionization front. The infrared spectroscopic observations are powerful tools to estimate the fundamental physical properties of the high-mass YSOs. The high-mass YSO M17-IRS5 is confirmed to a face-on protostar-disk system with a central star mass about 7-9 solar masses, and age about 1x10^5 years. The medium resolution IR spectra (R=1500) of M17 IRS5 show no emission lines, indicating very weak accretion feature. However, further high-resolution infrared imaging and spectroscopic observations will be of great value to determine the accretion rate of M17 IRS5 and the disk structure of it.