Bibcode
Dell'Agli, F.; Di Criscienzo, M.; Boyer, M. L.; García-Hernández, D. A.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 460, Issue 4, p.4230-4241
Fecha de publicación:
8
2016
Número de citas
23
Número de citas referidas
21
Descripción
We used models of thermally pulsing asymptotic giant branch (AGB) stars,
which also describe the dust-formation process in the wind, to interpret
the combination of near- and mid-infrared photometric data of the dwarf
galaxy IC 1613. This is the first time that this approach is extended to
an environment different from the Milky Way and the Magellanic Clouds
(MCs). Our analysis, based on synthetic population techniques, shows
nice agreement between the observations and the expected distribution of
stars in the colour-magnitude diagrams obtained with JHK and Spitzer
bands. This allows a characterization of the individual stars in the AGB
sample in terms of mass, chemical composition and formation epoch of the
progenitors. We identify the stars exhibiting the largest degree of
obscuration as carbon stars evolving through the final AGB phases,
descending from 1-1.25 M⊙ objects of metallicity Z =
10-3 and from 1.5-2.5 M⊙ stars with Z = 2
× 10-3. Oxygen-rich stars constitute the majority of
the sample (˜65 per cent), mainly low-mass stars (<2
M⊙) that produce a negligible amount of dust
(≤10-7 M⊙ yr-1). We predict the
overall dust-production rate from IC 1613, mostly determined by carbon
stars, to be ˜6 × 10-7 M⊙
yr-1 with an uncertainty of 30 per cent. The capability of
the current generation of models to interpret the AGB population in an
environment different from the MCs opens the possibility to extend this
kind of analysis to other Local Group galaxies.