Chandra Detection of an Evolved Population of Young Stars in Serpens South

Journal Article · Fri Jun 01 04:00:00 EDT 2018 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AABE82· OSTI ID:22897486

Winston, E.; Wolk, S. J. ^[1]; Gutermuth, R. ^[2]

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1. Harvard Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
2. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

We present a Chandra study of the deeply embedded Serpens South star-forming region, examining cluster structure and disk properties at the earliest stages. In total, 152 X-ray sources are detected. Combined with Spitzer and 2MASS photometry, 66 X-ray sources are reliably matched to an IR counterpart. We identify 21 class I, 6 flat spectrum, 16 class II, and 18 class III young stars; 5 were unclassified. Eighteen sources were variable in X-rays, 8 exhibiting flare-like emission and one source being periodic. The cluster’s X-ray luminosity distance was estimated: the best match was to the nearer distance of 260 pc for the front of the Aquila Rift complex. The ratio of N {sub H} to A {sub K} is found to be ∼0.68 × 10{sup 22}, similar to that measured in other young low-mass regions, but lower than that measured in the interstellar medium and high-mass clusters (∼(1.6–2) × 10{sup 22}). We find that the spatial distribution closely follows that of the dense filament from which the stars have formed, with the class II population still strongly associated with the filament. There are four subclusters in the field, with three forming knots in the filament, and a fourth to the west, which may not be associated but may be contributing to the distributed class III population. A high percentage of diskless class IIIs (upper limit 30% of classified X-ray sources) in such a young cluster could indicate that processing of disks is influenced by the cluster environment and is not solely dependent on timescale.

• OSTI ID: 22897486
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 6 Vol. 155; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMIC X-RAY SOURCES
DETECTION
DISTANCE
EMISSION
INTERSTELLAR SPACE
LUMINOSITY
MAIN SEQUENCE STARS
MASS
PERIODICITY
PHOTOMETRY
SPATIAL DISTRIBUTION
SPECTRA