Kinematic evidence for feedback-driven star formation in NGC 1893

TL;DR

This study provides kinematic evidence that feedback from massive stars in NGC 1893 triggers sequential star formation, contributing significantly to the cluster's stellar population and supporting the self-regulating star formation model.

Contribution

It offers high-resolution spectroscopic evidence of feedback-driven star formation and quantifies its role in OB association formation, which was previously uncertain.

Findings

Newborn stars and gas are moving away from ionizing sources.

Sequential star formation occurs within about 1 Myr over 9 parsecs.

At least 18% of the cluster's stars formed via feedback from massive stars.

Abstract

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