# The Sejong Open cluster Survey (SOS) VI. A small star-forming region in the high Galactic latitude molecular cloud MBM 110

## TL;DR

This study characterizes the small star-forming region MBM 110 using optical, infrared, and astrometric data, revealing its age, mass, and star formation efficiency, and highlighting its significance in understanding galactic star formation.

## Contribution

First detailed multi-wavelength analysis of MBM 110, confirming its properties and emphasizing the role of small star-forming regions in galaxy-wide star formation.

## Key findings

- MBM 110 is at 375 pc distance, confirmed by Gaia parallax.
- Age of MBM 110 is between 1.9 and 3.1 million years.
- Star formation efficiency is approximately 1.4%.

## 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 analyze 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 +/- 13 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 Myr and 3.1 Myr depending on the adopted pre-main sequence evolution model. The total stellar mass of MBM 110 is between 16 M_sun (members only) and 23 M_sun (including probable members). The star formation efficiency is estimated to be about 1.4%. 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 Halpha luminosity may underestimate the actual star formation rate. We also confirm a young brown dwarf member based on photometry, spectroscopy, and astrometry.