Spitzer Observations of the HII Region NGC 2467: An Analysis of Triggered Star Formation

Abstract

We present new Spitzer Space Telescope observations of the region NGC 2467, and use these observations to determine how the environment of an HII region affects the process of star formation. Our observations comprise IRAC (3.6, 4.5, 5.8, and 8.0 um) and MIPS (24 um) maps of the region, covering approximately 400 square arcminutes. The images show a region of ionized gas pushing out into the surrounding molecular cloud, powered by an O6V star and two clusters of massive stars in the region. We have identified as candidate Young Stellar Objects (YSOs) 45 sources in NGC 2467 with infrared excesses in at least two mid-infrared colors. We have constructed color-color diagrams of these sources and have quantified their spatial distribution within the region. We find that the YSOs are not randomly distributed in NGC 2467; rather, over 75% of the sources are distributed at the edge of the HII region, along ionization fronts driven by the nearby massive stars. The high fraction of YSOs in NGC 2467 that are found in proximity to gas that has been compressed by ionization fronts supports the hypothesis that a significant fraction of the star formation in NGC 2467 is triggered by the massive stars and the expansion of the HII region. At the current rate of star formation, we estimate at least 25-50% of the total population of YSOs formed by this process.

arXiv commentAccepted to the Astrophysical Journal, set to appear in Volume 701; 18 pages, 13 figures, 4 tables. This version reflects a few major changes made in the accepted version, including new figures

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Cited by in corpus (25)

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• Driving Turbulence and Triggering Star Formation by Ionizing Radiation
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• The dangers of being trigger--happy
• iVINE - Ionization in the parallel tree/SPH code VINE: First results on the observed age-spread around O-stars
• Ionization--induced star formation IV: Triggering in bound clusters
• Ionization--induced star formation V: Triggering in partially unbound clusters
• Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. I. Varied Shock Speeds
• Mixing of Clumpy Supernova Ejecta into Molecular Clouds
• Spitzer Analysis of HII Region Complexes in the Magellanic Clouds: Determining a Suitable Monochromatic Obscured Star Formation Indicator
• Detecting stellar-wind bubbles through infrared arcs in HII regions
• Classical T Tauri stars with VPHAS$+$: I: H$\alpha$ and $u$-band accretion rates in the Lagoon Nebula M8
• Ionisation-induced star formation III: Effects of external triggering on the IMF in clusters
• Testing Triggered Star Formation in Six H II Regions
• Understanding formation of young, distributed low-mass stars and clusters in the W4 cloud complex
• The massive multiple system HD 64315
• The physical properties of Cluster Chains
• Star forming activity in the H II regions associated with IRAS 17160-3707 complex
• A multiwavelength investigation of the HII region S311: Young stellar population and star formation
• Star formation in the S233 region
• The interaction of hydrodynamic shocks with self-gravitating clouds
• The statistical analysis of the dynamical evolution of the open clusters
• Deep optical survey of the stellar content of Sh2-311 region
• Investigating star formation scenarios in the Milky Way using YSO distributions -- A pilot study