Astrophys. J., 859, 166-166 (2018/June-1)
A new look at the molecular gas in M42 and M43: possible evidence for cloud-cloud collision that triggered formation of the OB stars in the Orion Nebula Cluster.
FUKUI Y., TORII K., HATTORI Y., NISHIMURA A., OHAMA A., SHIMAJIRI Y., SHIMA K., HABE A., SANO H., KOHNO M., YAMAMOTO H., TACHIHARA K. and ONISHI T.
Abstract (from CDS):
The Orion Nebula Cluster toward the H II region M42 is the most outstanding young cluster at the smallest distance (410 pc) among the rich high-mass stellar clusters. By newly analyzing the archival molecular data of the 12CO(J = 1-0) emission at 21'' resolution, we identified at least three pairs of complementary distributions between two velocity components at 8 and 13 km s–1. We present a hypothesis that the two clouds collided with each other and triggered formation of the high-mass stars, mainly toward two regions including the nearly 10 O stars in M42 and the B star, NU Ori, in M43. The timescale of the collision is estimated to be ∼0.1 Myr by a ratio of the cloud size and velocity corrected for projection, which is consistent with the age of the youngest cluster members less than 0.1 Myr. The majority of the low-mass cluster members were formed prior to the collision in the last Myr. We discuss the implications of the present hypothesis and the scenario of high-mass star formation by comparing with the other eight cases of triggered O-star formation via cloud-cloud collision.
© 2018. The American Astronomical Society. All rights reserved.
ISM: clouds - ISM: kinematics and dynamics - ISM: molecules - stars: formation
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