Clusters within Clusters: Spitzer & Chandra Observations of Subclusters in RCW 38
Abstract
The majority of young stars are believed to form in star clusters. The effect this has on their circumstellar environments will depend on the star formation history and structure of the cluster itself. At a distance of 1.7 kpc, RCW 38 contains an estimated 20-40 OB stars and an estimated total of ∼ 10^3 members. Here we use the mid-IR Spitzer IRAC observations to identify young stellar objects with circumstellar emission in an extended region around RCW 38. Elevated X-ray emission from young stars enables us to also locate diskless young members using the Chandra ACIS X-ray observation. We identify 624 young stellar objects in RCW 38. Of these, 226 were detected in X-rays. The YSOs have the following evolutionary classes: 23 class I, 90 flat spectrum, 437 class II, and 74 class III. Of the YSOs, 9 class I, 18 flat spectrum, 125 class II, and 74 class III were also detected in the Chandra X-ray observation. Through a study of the spatial distribution of the YSOs we find strong evidence of subclustering in the region, particularly among the most massive and variable stars. Four subclusters are identified; the central region of star formation in RCW 38 is surrounded by three subclusters and distributed young stars. This indicates that star formation is ongoing over a much larger area of the region than previously realised.
- Publication:
-
Stellar Clusters & Associations: A RIA Workshop on Gaia
- Pub Date:
- 2011
- Bibcode:
- 2011sca..conf..161W