2007/07/18 by Andrew Walsh, Andrew J. Walsh, Walsh, Andrew J. +10
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.0707.2622
13 pages 11 figures
arxiv created 2007/07/18 · openalex publication_date 2007/07/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report on Australia Telescope observations of the massive star forming region G305.2+0.2 at 1.2 cm. We detected emission in five molecules towards G305A, confirming its hot core nature. We determined a rotational temperature of 26 K for methanol. A non-LTE excitation calculation suggests a kinematic temperature of order 200 K. A time dependent chemical model is also used to model the gas phase chemistry of the hot core associated with G305A. A comparison with the observations suggest an age of between 2 x104 and 1.5 x105 years. We also report on a feature to the SE of G305A which may show weak Class I methanol maser emission in the line at 24.933 GHz. The more evolved source G305B does not show emission in any of the line tracers, but strong Class I methanol maser emission at 24.933 GHz is found 3\arcsec to the east. Radio continuum emission at 18.496 GHz is detected towards two \hii regions. The implications of the non-detection of radio continuum emission toward G305A and G305B are also discussed.