The stellar content of NGC 6789, a blue compact dwarf galaxy in the Local Void

We find that NGC 6789 is the most nearby example of a blue compact dwarf galaxy known to date. With the help of the Wide Field Planetary Camera 2 aboard the Hubble Space Telescope, we resolve NGC 6789 into over 15,000 point sources in the V and I bands. The young stars of NGC 6789 are found exclusively near the center of the galaxy. The red giant population identified at large galactocentric radii yields a distance of about 3.6 Mpc, a stellar metallicity [Fe/H] of about -2, and a minimum age of about 1 Gyr. Despite its isolated location in the Local Void, its low metallicity, and its active star formation, the properties of NGC 6789 are clearly not those of a galaxy in formation.