The following document lists the file abstract/JBLOMMAE_GC_OHIR1.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
We propose to determine accurate luminosities for a sample of 35 OH/IR stars within one degree from the galactic center (GC). This will be done by measuring their spectral energy distribution (SED) between 2 and 60 micron. The 25-60 micron part of the SED can only be done from space and ground based observations between 10 and 20 micron lack sensitivity due to poor atmospheric transmission. ISO is the only observatory that contains the instruments to cover the entire wavelength range of the SED's. The OH/IR stars in the GC were discovered with a sensitive OH 1612 MHz survey with the VLA (Lindqvist et al. 1992a). After separating the total sample of 136 OH/IR stars into stars with low and high circumstellar shell expansion velocities, Lindqvist et al. (1992b) found that the kinematical and spatial distributions of the two samples are different and they suggested that they must have different ages. The aim of this proposal is two fold. First, we want to determine the age distribution of the two kinematically different subsamples. The ages will be derived from their luminosities (through comparison with state of the art AGB evolution models) and metallicities. We will determine accurate luminosities in this project. We will determine metallicities from groundbased spectroscopy. Second, we will use these OH/IR stars to study the last stages of AGB evolution not hampered by large uncertainties in distances. We will determine luminosities and mass loss rates through modelling of the energy distributions. From groundbased studies we will determine other important quantities such as pulsation periods and metallicities. This unique set of data will allow sensitive tests of current AGB evolution theories.