Massive star formation in the Carina nebula complex and Gum 31 -- I. The Carina nebula complex

• Published in: arXiv.org
• Main Authors: Fujita, Shinji, Sano, Hidetoshi, Enokiya, Rei, Hayashi, Katsuhiro, Kohno, Mikito, Tsuge, Kisetsu, Tachihara, Kengo, Nishimura, Atsushi, Ohama, Akio, Yamane, Yumiko, Ohno, Takahiro, Yamada, Rin, Fukui, Yasuo
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 15.09.2020
• Subjects: Gum nebula; Massive stars; Molecular clouds; Physics - Astrophysics of Galaxies; Signatures; Spatial distribution; Star & galaxy formation; Star clusters; Star formation; Telescopes
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2003.13925

Herein, we present results from observations of the 12CO (J=1-0), 13CO (J=1-0), and 12CO (J=2-1) emission lines toward the Carina nebula complex (CNC) obtained with the Mopra and NANTEN2 telescopes. We focused on massive-star-forming regions associated with the CNC including the three star clusters Tr14, Tr15, and Tr16, and the isolated WR-star HD92740. We found that the molecular clouds in the CNC are separated into mainly four clouds at velocities -27, -20, -14, and -8 km/s. Their masses are 0.7x10^4Msun, 5.0x10^4 Msun, 1.6x10^4 Msun, and 0.7x10^4 Msun, respectively. Most are likely associated with the star clusters, because of their high 12CO (J=2-1)/12CO (J=1-0) intensity ratios and their correspondence to the Spitzer 8 micron distributions. In addition, these clouds show the observational signatures of cloud--cloud collisions. In particular, there is a V-shaped structure in the position--velocity diagram and a complementary spatial distribution between the -20 km/s cloud and the -14 km/s cloud. Based on these observational signatures, we propose a scenario wherein the formation of massive stars in the clusters was triggered by a collision between the two clouds. By using the path length of the collision and the assumed velocity separation, we estimate the timescale of the collision to be ~1 Myr. This is comparable to the ages of the clusters estimated in previous studies.