YOUNG STELLAR OBJECTS IN THE MASSIVE STAR-FORMING REGION W49.
G Saral1,2, J L Hora1, S E Willis1
1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA.
The Astrophysical Journal
|September 16, 2020
Summary
We identified over 1,200 young stellar objects (YSOs) in the W49 star-forming complex using infrared data. W49 hosts the richest population of YSOs, with seven subclusters, indicating active massive star formation.
Area of Science:
- Astronomy and Astrophysics
- Star Formation Studies
- Galactic Evolution
Background:
- W49 is a prominent, young, and luminous massive star-forming region in the Milky Way galaxy.
- Understanding the early stages of massive star formation is crucial for galactic evolution models.
Purpose of the Study:
- To locate protostars and associated young star clusters within the W49 star-forming complex.
- To create a comprehensive catalog of young stellar objects (YSOs) in W49.
- To analyze the clustering of YSOs to understand star formation evolution.
Main Methods:
- Utilized Spitzer/Infrared Array Camera (IRAC) data for high-resolution imaging.
- Combined data from IRAC, MIPS, Two Micron All Sky Survey, and UKIDSS for YSO identification and classification.
- Employed color-color and color-magnitude diagrams to classify YSOs into different evolutionary stages (Class 0/I, Class II, transition disk).
- Applied a minimal spanning tree method to analyze YSO distribution and identify clusters.
Main Results:
- Identified 232 Class 0/I YSOs, 907 Class II YSOs, and 74 transition disk candidates.
- Found that 52% of YSOs belong to clusters with at least 7 members.
- Determined a Class II/I object ratio of 2.1.
- Discovered seven distinct subclusters of YSOs within W49.
Conclusions:
- W49 exhibits the richest population of YSOs among the compared star-forming regions (W49, G305, G333).
- The identified subclusters and high YSO density in W49 highlight its significance as a major site of ongoing massive star formation.
- The results provide valuable insights into the processes governing the formation of massive stars and their environments.
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