OH/IR stars in the inner bulge detected by ISOGAL
Blommaert, J. A. D. L.; Ganesh, S.; Omont, A.; Schultheis, M.; Schuller, F.; Ortiz, R.; Habing, H. J.; Copet, E.; Messineo, M.
Brazil, Netherlands, Spain, Belgium, France, India
Abstract
We present a study of known OH/IR stars in the inner bulge, observed by the ISOGAL survey at lambda = 6.8 mu m and lambda = 14.9 mu m. Bolometric corrections and luminosities are computed, based on near and mid-infrared data. The vast majority of the sources exhibit mass-loss rates in the range: 3 x 10-7 up to a few times 10-5 Msun/year. The bolometric magnitude distribution peaks at Mbol = -5.0. There is no clear evidence that the luminosity is related to the expansion velocity of the envelope for the sample in the bulge observed by ISOGAL. We find that the bulge OH/IR stars do not follow a period-luminosity (PL) law and that they are systematically less luminous than the OH/IR extension of the PL relationship for Miras. Based on observations with ISO, an ESA project with instruments funded by ESA member states. This is paper No. 6 in a refereed journal based on data from the ISOGAL project.