THE PROPERTIES OF X-RAY LUMINOUS YOUNG STELLAR OBJECTS IN THE NGC 1333 AND SERPENS EMBEDDED CLUSTERS

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/140/1/266· OSTI ID:21443288

Winston, E ^[1]; Megeath, S T ^[2]; Wolk, S J; Spitzbart, B; Covey, K; Hora, J L; Myers, P C; Fazio, G G ^[3]; Gutermuth, R ^[4]; Allen, L E ^[5]; Hernandez, J ^[6]; Muzerolle, J ^[7]

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1. School of Physics, University of Exeter, Exeter EX4 4QL (United Kingdom)
2. Ritter Observatory, Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States)
3. Harvard Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
4. Five Colleges Astronomy Department, Smith College, Northampton, MA 01027 (United States)
5. NOAO, Tucson, AZ (United States)
6. Centro de Investigaciones de Astronomia, Merida 5101-A (Venezuela, Bolivarian Republic of)
7. Space Telescope Science Institute, Baltimore, MD (United States)

We present new Chandra X-ray data of the NGC 1333 embedded cluster and combine these data with existing Chandra data, Spitzer photometry, and ground-based spectroscopy of both the NGC 1333 and Serpens cloud core clusters to perform a detailed study of the X-ray properties of two of the nearest embedded clusters to the Sun. We first present new, deeper observations of NGC 1333 with Chandra ACIS-I and combine these with existing Spitzer observations of the region. In NGC 1333, a total of 95 cluster members are detected in X-rays of which 54 were previously identified in the Spitzer data. Of the Spitzer-identified sources, we detected 23% of the Class I protostars, 53% of the flat-spectrum sources, 52% of the Class II, and 50% of the transition disk young stellar objects (YSOs). Forty-one Class III members of the cluster are identified, bringing the total identified YSO population to 178. The X-ray luminosity functions (XLFs) of the NGC 1333 and Serpens clusters are compared to each other and the Orion Nebula Cluster (ONC). Based on a comparison of the XLFs of the Serpens and NGC 1333 clusters to the previously published ONC, we obtain a new distance for the Serpens cluster of 360{sup +22}{sub -13} pc. Using our previously published spectral types, effective temperatures, and bolometric luminosities, we analyze the dependence of the X-ray emission on the measured stellar properties. The X-ray luminosity was found to depend on the calculated bolometric luminosity as in previous studies of other clusters. We examine the dependence of L{sub X} on stellar surface area and effective temperature, and find that L{sub X} depends primarily on the stellar surface area. In the NGC 1333 cluster, the Class III sources have a somewhat higher X-ray luminosity for a given surface area. We also find evidence in NGC 1333 for a jump in the X-ray luminosity between spectral types of M0 and K7, we speculate that this may result from the presence of radiative zones in the K-stars. The gas column density versus extinction in the NGC 1333 parental molecular cloud was examined using the hydrogen column density determined from the X-ray absorption to the embedded stars and the K-band extinction measured to those stars. In NGC 1333, we find N{sub H} = 0.89 {+-} 0.13 x 10{sup 22} A{sub K} , this is lower than expected of the standard interstellar medium but similar to that found previously in the Serpens cloud core.

• OSTI ID: 21443288
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 140, Issue 1; Other Information: DOI: 10.1088/0004-6256/140/1/266; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
BOLOMETERS
EMISSION
HYDROGEN
LUMINOSITY
MATTER
NEBULAE
PHOTOMETRY
PROTOSTARS
SPECTRA
SPECTROSCOPY
SUN
SURFACE AREA
X RADIATION
ELECTROMAGNETIC RADIATION
ELEMENTS
IONIZING RADIATIONS
MAIN SEQUENCE STARS
MEASURING INSTRUMENTS
NONMETALS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SORPTION
STARS
SURFACE PROPERTIES