Kinematic evidence for feedback-driven star formation in NGC 1893

Abstract

OB associations are the prevailing star forming sites in the Galaxy. Up to\nnow, the process of how OB associations were formed remained a mystery. A\npossible process is self-regulating star formation driven by feedback from\nmassive stars. However, although a number of observational studies uncovered\nvarious signposts of feedback-driven star formation, the effectiveness of such\nfeedback has been questioned. Stellar and gas kinematics is a promising tool to\ncapture the relative motion of newborn stars and gas away from ionizing\nsources. We present high-resolution spectroscopy of stars and gas in the young\nopen cluster NGC 1893. Our findings show that newborn stars and the tadpole\nnebula Sim 130 are moving away from the central cluster containing two O-type\nstars, and that the timescale of sequential star formation is about 1 Myr\nwithin a 9 parsec distance. The newborn stars formed by feedback from massive\nstars account for at least 18 per cent of the total stellar population in the\ncluster, suggesting that this process can play an important role in the\nformation of OB associations. These results support the self-regulating star\nformation model.\n