The nature of Sk-67 degrees 18 in the Large Magellanic Cloud: A multiple system with an O3f* component

We present the results of photometric and spectroscopic observations obtain ed between 1980 and 1996, which show that the bright star Sk -67 degrees 18 in the Large Magellanic Cloud (LMC) is a multiple star which contains an e clipsing binary system. Our spectra show that this is an Of + O type binary , where the primary is probably of type O3f*. The orbital period of the ecl ipsing binary is almost exactly 2 days, which considerably compromises the obtaining of data with suitable phase coverage. Furthermore, from our radia l velocity analysis of the spectral lines, Sk -67 degrees 18 appears to be a multiple system consisting of at least two pairs of short-period binaries .