Two-Dimensional Molecular Gas and ongoing star formation around H II region Sh2-104

Abstract

We performed a multiwavelength study towards HII region Sh2-104. New maps of 12CO J=1-0 and 13CO J=1-0 were obtained from the Purple Mountain Observatory (PMO) 13.7 m radio telescope. Sh2-104 displays a double-ring structure. The outer ring with a radius of 4.4 pc is dominated by 12 um, 500 um, 12CO J=1-0, and 13CO J=1-0 emission, while the inner ring with a radius of 2.9 pc is dominated by 22 um and 21 cm emission. We did not detect CO emission inside the outer ring. The north-east portion of the outer ring is blueshifted, while the south-west portion is redshifted. The present observations have provided evidence that the collected outer ring around Sh2-104 is a two-dimensional structure. From the column density map constructed by the Hi-GAL survey data, we extract 21 clumps. About 90\% of all the clumps will form low-mass stars. A power-law fit to the clumps yields M=281Msun(r/pc)^1.31. The selected YSOs are associated with the collected material on the edge of Sh2-104. The derived dynamical age of Sh2-104 is 1.6*10^6 yr. Compared the Sh2-104 dynamical age with the YSOs timescale and the fragmentation time of the molecular ring, we further confirm that collect-and-collapse process operates in this region, indicating a positive feedback from a massive star for surrounding gas.

19 pages, 14 figures, Accepted for publication in ApJ

References in corpus (10)

• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• A Classification Scheme for Young Stellar Objects Using the WIDE-FIELD INFRARED SURVEY EXPLORER AllWISE Catalog: Revealing Low-Density Star Formation in the Outer Galaxy
• IR Dust Bubbles: Probing the Detailed Structure and Young Massive Stellar Populations of Galactic HII Regions
• Star formation around RCW 120, the perfect bubble
• Triggered massive-star formation on the borders of Galactic HII regions. IV- Star formation at the periphery of Sh2-212
• Mopra CO Observations of the Bubble HII Region RCW120
• The molecular complex associated with the Galactic HII region Sh2-90: a possible site of triggered star formation
• Unveiling the birth and evolution of the HII region Sh2-173
• Expanding Shell and Star Formation in the Infrared Dust Bubble N6
• Star formation associated with a large-scale infrared bubble

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• Ionising feedback from an O star formed in a shock-compressed layer
• The Molecular Clouds associated with the H II Regions/Candidates between $l=207.7^{\circ }$ and $l=211.7^{\circ }$