MILLIARCSECOND-RESOLUTION OBSERVATIONS OF M-GIANTS IN THE NEAR-INFRARED BY LUNAR OCCULTATIONS

Near-infrared lunar occultation observations of six M giants, namely I RC + 20190, NSV 1529, IRC + 00198, BQ Ori, IRC + 10194 and IRC + 10024 , in the spectral range M2-M7 are reported. Among these, four giants ( NSV 1529, BQ Ori, IRC + 10194 and IRC + 1.0024) are resolved from our observations carried out at 2.2 mu m, resulting in accurate estimation s of the angular size and the stellar effective temperature of these s ources. The peculiarity of IRC + 10194 and the problem of its real eff ective temperature are discussed. Upper limits on the stellar angular size for the other two giants have been derived.