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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
PubMed
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.

Keywords:
infrared: starsstars: early-typestars: formationstars: pre-main sequence

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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.