The massive star-forming region G323.74-0.26

Abstract

We report near-infrared molecular hydrogen and Brackett observations towards the massive star formation site G323.74-0.26. The region contains an H ii region, 30 arcsec across, and two Class II methanol maser sites, which are separate from the H ii region. We show that the spectral type of the star powering the H ii region is B0. We also show that at least one of the maser sites is powered by an infrared source that appears to be at least as luminous as the star responsible for the H ii region. However, neither of the two stars associated with the methanol maser sites shows any signs of radio continuum emission above 0.2 mJy. For at least one of these maser sites, this shows a real deficiency in the radio continuum flux, which we suggest is an indication that the star is in an early stage of development, before its H ii region becomes visible, or it is a multiple intermediate mass star system. A shocked molecular hydrogen outflow is seen extending from one of the maser sites towards the west and possibly in a fan shape, suggesting that the stars associated with the maser sites are indeed at a very early stage of evolution.