Massive star formation in the Carina nebula complex and Gum 31. II. A cloud–cloud collision in Gum 31

Abstract We present the results of analyses 12CO (J = 1–0), 13CO and 2–1) emission data toward Gum 31. Three molecular clouds separated in velocity were detected at −25, −20, −10 km s−1. The structure 31 cannot be interpreted as an expanding motion. Two them, −25 s−1 cloud −20 cloud, are likely to associated with 31, because their 2–1)$/$12CO 1–0) intensity ratios high. found that these two show observational signatures cloud–cloud collisions (CCCs): a complementary spatial distribution V-shaped (bridge features) position–velocity diagram. In addition, morphology structures very similar numerical simulations conducted by previous studies. propose scenario collided triggered formation massive star system HD 92206 This can explain offset stars from center simultaneously. timescale collision was estimated ∼1 Myr using ratio between path length assumed separation. is consistent CCCs Carina Nebula Complex our study.