منطقة هيدروجين II
Stock 16 is a very young Galactic open cluster in the H II region RCW 75 (= Gum 48a). This region lies at the end of an "elephant trunk" shaped molecular cloud and may be a region with triggered star formation. The primary ionizing source for the H II region is the star HD 115455, with spectral type O7.5 III.