I present a comprehensive study of the MBM12 young association ( MBM12A ) .
By combining infrared ( IR ) photometry from the Two-Micron All-Sky Survey ( 2MASS ) survey with new optical imaging and spectroscopy , I have performed a census of the MBM12A membership that is complete to 0.03 M _ { \odot } ( H \sim 15 ) for a 1.75 \arcdeg \times 1.4 \arcdeg field encompassing the MBM12 cloud .
I find five new members with masses of 0.1-0.4 M _ { \odot } and a few additional candidates that have not been observed spectroscopically .
From an analysis of optical and IR photometry for stars in the direction of MBM12 , I identify M dwarfs in the foreground and background of the cloud .
By comparing the magnitudes of these stars to those of local field dwarfs , I arrive at a distance modulus 7.2 \pm 0.5 ( 275 pc ) to the MBM12 cloud ; it is not the nearest molecular cloud and is not inside the local bubble of hot ionized gas as had been implied by previous distance estimates of 50-100 pc .
I have also used Li strengths and H-R diagrams to constrain the absolute and relative ages of MBM12A and other young populations ; these data indicate ages of 2 ^ { +3 } _ { -1 } Myr for MBM12A and \sim 10 Myr for the TW Hya and \eta Cha associations .
MBM12A may be a slightly evolved version of the aggregates of young stars within the Taurus dark clouds ( \sim 1 Myr ) near the age of the IC 348 cluster ( \sim 2 Myr ) .