Stellar contents and star formation in the young star cluster Be 59 |
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| Authors: | A K Pandey Saurabh Sharma K Ogura D K Ojha W P Chen B C Bhatt S K Ghosh |
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| Institution: | Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan;Tata Institute of Fundamental Research, Mumbai 400 005, India;Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital 263 129, India;Kokugakuin University, Higashi, Shibuya-ku, Tokyo 150-8440, Japan;CREST, Indian Institute of Astrophysics, Hosakote 562 114, India |
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| Abstract: | We present UBV I c CCD photometry of the young open cluster Be 59 with the aim to study the star formation scenario in the cluster. The radial extent of the cluster is found to be ～10 arcmin (2.9 pc). The interstellar extinction in the cluster region varies between E ( B ? V ) ? 1.4 to 1.8 mag. The ratio of total-to-selective extinction in the cluster region is estimated as 3.7 ± 0.3 . The distance of the cluster is found to be 1.00 ± 0.05 kpc . Using near-infrared (NIR) colours and slitless spectroscopy, we have identified young stellar objects (YSOs) in the open cluster Be 59 region. The ages of these YSOs range between <1 and ～2 Myr, whereas the mean age of the massive stars in the cluster region is found to be ～2 Myr. There is evidence for second-generation star formation outside the boundary of the cluster, which may be triggered by massive stars in the cluster. The slope of the initial mass function, Γ, in the mass range 2.5 < M /M⊙≤ 28 is found to be ?1.01 ± 0.11 which is shallower than the Salpeter value (?1.35), whereas in the mass range 1.5 < M /M⊙≤ 2.5 the slope is almost flat. The slope of the K -band luminosity function is estimated as 0.27 ± 0.02 , which is smaller than the average value (～0.4) reported for young embedded clusters. Approximately 32 per cent of Hα emission stars of Be 59 exhibit NIR excess indicating that inner discs of the T Tauri star (TTS) population have not dissipated. The Midcourse Space Experiment (MSX) and IRAS-HIRES images around the cluster region are also used to study the emission from unidentified infrared bands and to estimate the spatial distribution of optical depth of warm and cold interstellar dust. |
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| Keywords: | open clusters and associations: individual: Be 59 stars: formation stars: luminosity function mass function stars: pre-main-sequence |
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