Census of the Young Stellar Population in the Galactic H ii Region Sh2-242

Journal Article · Wed Apr 01 04:00:00 EDT 2020 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AB737A· OSTI ID:23013157

Panja, Alik; Mondal, Soumen; Das, Ramkrishna ^[1]; Dutta, Somnath ^[2]; Joshi, Santosh; Lata, Sneh ^[3]

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1. S.N. Bose National Centre for Basic Sciences, Kolkata 700106 (India)
2. Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China)
3. Aryabhatta Research Institute of Observational Sciences, Nainital 263002 (India)

We present here identification and characterization of the young stellar population associated with an active star-forming site Sh2-242. We used our own new optical imaging and spectroscopic observational data, as well as several archival catalogs, e.g., Pan-STARRS 1, Gaia DR2, IPHAS, Wide-field InfraRed Camera, 2MASS, and Spitzer. Slit spectroscopic results confirm the classification of the main ionizing source BD+26 980 as an early-type star of spectral type B0.5 V. The spectrophotometric distance of the star is estimated as 2.08 ± 0.24 kpc, which confirms the source as a member of the cluster. An extinction map covering a large area (diameter ∼50′) is generated with H and K photometry toward the region. From the map, three distinct locations of peak extinction complexes (A {sub V} ≃ 7–17 mag) are identified for the very first time. Using the infrared color excess, a total of 33 Class I and 137 Class II young objects are classified within the region. The IPHAS photometry reveals classification of 36 Hα emitting sources, which might be class II objects. Among 36 Hα emitting sources, 5 are already identified using infrared excess emission. In total, 201 young objects are classified toward S242 from this study. The membership status of the young sources is further windowed with the inclusion of parallax from the Gaia DR2 catalog. Using the optical and infrared color–magnitude diagrams, the young stellar objects are characterized with an average age of ∼1 Myr and masses in the range 0.1–3.0 M {sub ☉}. The census of the stellar content within the region is discussed using combined photometric and spectroscopic data.

• OSTI ID: 23013157
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 4 Vol. 159; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CLASSIFICATION
DISTANCE
EMISSION
GALAXIES
INCLUSIONS
MASS
PHOTOMETRY
SPECTROPHOTOMETRY
STAR EVOLUTION