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) o n timescales of 10 to 40 days. The variations in B-E and R-E are about equa l but the stars are slightly bluer when they an fainter. Medium resolution optical spectra show strong H alpha emission, weak H beta emission and abso rption 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 wi th 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 s trong 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 Galacti c 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.