4 Conclusions

We have carried out a high resolution spectrophotometric analysis of the bulge K giant star EROS-BLG-2000-5 while it was magnified due to microlensing. The derived stellar parameters are: $T_{\rm eff} = 3800\pm 200$ K, log $g = 1.0 \pm 0.5$, $\rm [Fe/H] = -0.3 \pm 0.3$, $\rm [O/Fe] \approx 0.0\pm 0.2$.

It is interesting to note that the metallicity is close to the mean value found by McWilliam & Rich (1994) for bulge giants in Baade's Window. Within uncertainties of distances it would be compatible either with a far side old disk giant, or a far side bulge giant.

It would be important to make efforts to calibrate the EROS magnitudes to final values in standard systems and to pursue this kind of microlensing surveys, since it provides a powerful means of observing faint distant objects, in particular in the bulge direction where these events are much more frequent.

Figure 3: Curve of growth of Ti I. Same symbols as in Fig. 2.

Figure 4: [OI] line region spectrum of the lensed star EROS-BLG-2000-5 (dotted line) compared to synthetic spectra computed with $\rm [O/Fe] = [Ti/Fe] = -0.2$, 0.0 and +0.2, showing the effect of the TiO bands on the continuum level.

Figure 5: [OI] line region spectrum of EROS-BLG-2000-5 (dotted line) compared to synthetic spectra computed with $\rm [O/Fe] = [Ti/Fe] = -0.2$, 0.0 and +0.2, and normalized to the observed spectrum, aiming to fit the [OI]6300.311 ${\rm\AA}$ line.

Acknowledgements

DM is supported by Fondecyt 1990440. BB and EB acknowledge partial financial support from the Brazilian agencies CNPq and Fapesp. SO acknowledges the Italian Ministero dell'Università e della Ricerca Scientifica e Tecnologica (MURST) under the program on "Stellar Evolution'' (Italy). KHC performed this work under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.