We report observations of the binary microlensing event OGLE-2018-BLG-0022, provided by the ROME/REA Survey, which indicate that the lens is a low-mass binary star consisting of M3 (0.375+/-0.020 Msun) and M7 (0.098+/-0.005 Msun) components. The lens is unusually close, at 0.998+/-0.047 kpc, compared with the majority of microlensing events, and despite its intrinsically low luminosity, it is likely that AO observations in the near future will be able to provide an independent confirmation of the lens masses.
@article{arxiv.1903.08733,
title = {OGLE-2018-BLG-0022: A Nearby M-dwarf Binary},
author = {R. A. Street and E. Bachelet and Y. Tsapras and M. P. G. Hundertmark and V. Bozza and M. Dominik and D. M. Bramich and A. Cassan and K. Horne and S. Mao and A. Saha and J. Wambsganss and Weicheng Zang and U. G. Jorgensen and P. Longa-Pena and N. Peixinho and S. Sajadian and M. J. Burgdorf and J. Campbell-White and S. Dib and D. F. Evans and Y. I. Fujii and T. C. Hinse and E. Khalouei and S. Lowry and S. Rahvar and M. Rabus and J. Skottfelt and C. Snodgrass and J. Southworth and J. Tregloan-Reed},
journal= {arXiv preprint arXiv:1903.08733},
year = {2019}
}