Mid-Infrared Imaging of Massive Young Stars

R. R. Billmeier, R. Jayawardhana, M. Marengo, D. Mardones, J. Alves

Formation of massive stars is a poorly understood process. Detailed

observations of high-luminosity young stellar objects (YSOs), often

embedded in dusty envelopes, could provide valuable clues to their

origin. Imaging in the mid-infrared allows us to investigate the

multiplicity of sources, characterize the immediate circumstellar

material, and connect the overall structure of the YSO environment on

both large and small scales. Here we present subarcsecond-resolution

mid-infrared images of nine young stellar objects: AFGL 961, AFGL 2136,

AFGL 4176, AFGL 7009S, G343.126, I17441, M8E-IR, S269-IRS2, and W33A.

The observations were obtained in two runs using the Thermal Infrared

Multi-Mode Instrument (TIMMI2) on the European Southern Observatory's

3.6-meter telescope in La Silla, Chile. Each target, with the exception

of AFGL 4176, has observations at both 11.9 microns and Q-band. M8E-IR

was also observed at 8.9 and 9.8 microns, while AFGL 961 and S269-IRS2

were imaged at 4.6 microns as well. We present photometry and contour

plots to show the infrared morphology of each target, several of which

reveal multiple sources and/or diffuse nebulosity. For example, we find

that M8E-IR has six separate sources clustered around the central point

source. In addition to I17441's central point source, there are three

fainter sources as well as a large bow-shaped nebulosity. We detect four

point sources toward AFGL 961 and extended diffuse mission associated

with S269-IRS2. We discuss the relation between our mid-infrared images

of these YSOs and previously available data on their near-infrared

morphology, silicate features, and CO outflows.

Department of Astrophysics
External organisation(s)
Michigan State University, Harvard-Smithsonian Center for Astrophysics, European Southern Observatory (Germany), Universidad de Chile
Bulletin of the American Astronomical Society
Publication date
Austrian Fields of Science 2012
103004 Astrophysics
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