LSS 1135: An O-type spectroscopic binary in the galactic OB association Bochum 7

From radial velocities derived from optical spectroscopic observations performed at CTIO, Chile, and CASLEO, Argentina, we have discovered that LSS 1135 is a single-lined O-type binary system with an orbital period of 2.7532 days. We present an analysis of the orbital elements of this system based on radial velocities of the He absorption lines. We classify the spectrum of LSS 1135 as O6.5V((f)). We also present spectral classifications and radial velocities for other seven OB stars in the region of Bochum 7, an OB association to which LSS 1135 belongs. Our data indicate a distance of 5.0 kpc for this star group.