Kinematic study of molecular gas in cometary globule – LBN 437

Abstract

Bright-rimmed, cometary-shaped star-forming globules, associated with H II regions, are remnants of compressed molecular shells exposed to ultraviolet radiation from central OB-type stars. The interplay between dense molecular gas and ionizing radiation, analysed through gas kinematics, provides significant insights into the nature and dynamic evolution of these globules. This study presents the results of a kinematic analysis of the cometary globule, Lynds’ Bright Nebula (LBN) 437, focusing on the first rotational transition of 12CO and C18O molecular lines observed using the Taeduk Radio Astronomy Observatory. The averaged 12CO spectrum shows a slightly skewed profile, suggesting the possibility of a contracting cloud. The molecular gas kinematics reveals signatures of infalling gas in the cometary head of LBN 437, indicating the initial stages of star formation. The mean infall velocity and mass infall rate towards the cometary head of LBN 437 are 0.25 km s−1 and 5.08 × 10−4 M yr−1, respectively, which align well with the previous studies on intermediate or high-mass star formation.