Luminous pre-main sequence stars in the LMC?

We report the serendipitous discovery of seven luminous irregular variables in the LMC by the EROS project. The stars have V similar or equal to 15(m) to 17(m), (B-E - R-E) similar or equal to 0(m), and vary by about 0.4(m) on timescales of 10 to 40 days. The variations in B-E and R-E are about equal but the stars are slightly bluer when they an fainter. Medium resolution optical spectra show strong H alpha emission, weak H beta emission and absorption lines of the higher Balmer lines. Absorption lines of He I, C III, O II and Si IV are present in the spectra of some of the stars. The spectral types derived from the presence or absence of the lines are between late-O and late-B. Effective temperatures and luminosities were derived from the energy distributions and independently from the EROS photometry combined with the approximate spectral types. The luminosity, derived from V, E(B - V), and the distance of the LMC, are in the range of 10(3) to 10(4) L.. The strong Hey emission, the spectral types, the luminosities and the irregular variations are similar (but not the same) to those of the Galactic pre-main sequence HAeBe stars (i.e. the Herbig Ae/Be stars). However the stars are about a factor 10 more luminous than the luminosity upper limit for Galactic HAeBe stars. This might be due to a shorter accretion timescale (tau(accr) = M-* /(M) over dot), or to the smaller dust-to-gas ratio in the LMC.