  We present the first results from a series of Chandra observations carried
out with the aim to examine the origin of X-ray emission in main-sequence late
B-type stars. We use high spatial resolution X-ray observations to enlighten
the prevalent speculation that previously unknown late-type or low-mass
companion stars are the sites of the X-ray emission, instead of the B-type
primaries. Here we present the results for HD1685, HD113703, HD123445,
HD133880, and HD169978. Adaptive optics observations have recently revealed at
least one faint object near each of these B-type stars (at separation of 1-6").
Four of the new infrared objects show infrared colors and magnitudes typical
for low-mass pre-main sequence stars, and are likely true companions to the
10-50 Myr old B-type stars. These multiple systems are now resolved for the
first time in X-ray light.
