The HII Region KR 140: Spontaneous Formation of a High Mass Star

Abstract

We have used a multiwavelength data set from the Canadian Galactic Plane Survey (CGPS) to study the Galactic HII region KR 140, both on the scale of the nebula itself and in the context of the star forming activity in the nearby W3/W4/W5 complex of molecular clouds and HII regions. From both radio and infrared data we have found a covering factor of about 0.5 for KR 140 and we interpret the nebula as a bowl-shaped region viewed close to face on. Extinction measurements place the region on the near side of its parent molecular cloud. The nebula is kept ionized by one O8.5 V(e) star, VES 735, which is less than a few million years old. CO data show that VES 735 has disrupted much of the original molecular cloud for which the estimated mass and density are about 5000 $M_{\odot }$ and 100 cm${}^{-3}$, respectively. KR 140 is isolated from the nearest star forming activity, in W3. Our data suggest that KR 140 is an example of spontaneous (i.e., non-triggered) formation of, unusually, a high mass star.

46 pages; includes 15 figures; accepted by the ApJ

References in corpus (1)

• A Mid-Infrared Galaxy Atlas (MIGA)

Cited by in corpus (10)

• Embedded Stellar Clusters in the W3/W4/W5 Molecular Cloud Complex
• Intergalactic HII Regions Discovered in SINGG
• The Diverse Stellar Populations of the W3 Star Forming Complex
• Herschel Observations of the W3 GMC: Clues to the Formation of Clusters of High-Mass Stars
• A Submillimeter View of Star Formation Near the HII Region KR 140
• Star Formation & Young Stellar Content in the W3 GMC
• Sequential and Spontaneous Star Formation Around the Mid-Infrared Halo HII Region KR 140
• CO Outflow Candidates Toward the W3/4/5 Complex I: The Sample and its Spatial Distribution
• Interaction Between HII Region and AFGL333-Ridge: Implications to the Star Formation Scenario
• Submillimeter and molecular views of three Galactic ring-like HII regions