Publications
of the
MPIfR
Optical & Infrared
Interferometry Group
K.-P. Schröder and J.M. Winters:
Assessment of the tip-AGB mass-loss using
synthetic stellar samples in
the (MBol, J-K) diagram
in
Cool Stars, Stellar Systems, and the Sun,
,
12th Cambridge Workshop 'The Future of Cool-Star Astrophysics' (2001), p. 1063-1068 (2003)
Abstract.
A new approach is presented here to interpret the large amount of IR
survey data in a most direct and quantitative way, by means of
modeling the, e.g., (MBol, J-K) diagram. Combining stellar
evolution with dust-driven wind models, we have produced a grid of
stellar evolution tracks (for solar abundances) with a mass-loss
description for carbon-rich tip-AGB stars derived from the latest
version of the self-consistent, pulsating Berlin wind models. By
random distribution in age and mass, dependent only on the given IMF,
a large synthetic sample of tip-AGB cool giant stars with very strong
mass loss has then been generated, including relevant IR properties.
The synthetic cool giant sample presented here is modeled on the
solar neighbourhood (d < 50pc) and its IMF, for 1000x more stars. It
provides a detailed inventory of the individual stellar mass loss, the
stellar masses (present and initial) and ages. From 5067 giants with
B-V > 1.4, only 14 objects are found in their brief (final 30000
years) superwind phase (J - K > 6.5). However, these 14 carbon-rich
tip-AGB giants produce more than 1/2 of the collective mass-loss of
the whole stellar sample. Since these crucial objects are likely to
be under-represented in observed samples, a synthetic sample is
required to account for them without bias.