The Sejong Open cluster Survey (SOS) VI. A small star-forming region in the high Galactic latitude molecular cloud MBM 110. Issue 3 (16th April 2019) - Sung, Hwankyung
ABSTRACT: We present optical photometric, spectroscopic data for the stars in the high Galactic latitude molecular cloud MBM 110. For the complete membership selection of MBM 110, we also analyse Wide-field Infrared Survey Explorer ( WISE ) mid-infrared data and Gaia astrometric data. Membership of individual stars is critically evaluated using the data mentioned above. The Gaia parallax of stars in MBM 110 is 2.667 ± 0.095 mas ($d = 375 \pm 13\, \mathrm{pc}$ ), which confirms that MBM 110 is a small star-forming region in the Orion–Eridanus superbubble. The age of MBM 110 is between 1.9 and 3.1 Myr depending on the adopted pre-main-sequence evolution model. The total stellar mass of MBM 110 is between 16 M⊙ (members only) and 23 M⊙ (including probable members). The star formation efficiency is estimated to be about 1.4 per cent. We discuss the importance of such small star formation regions in the context of the global star formation rate and suggest that a galaxy's star formation rate calculated from the Hα luminosity may underestimate the actual star formation rate. We also confirm a young brown dwarf member based on photometry, spectroscopy, and astrometry.