Bibcode
Boyer, M. L.; McQuinn, K. B. W.; Groenewegen, M. A. T.; Zijlstra, A. A.; Whitelock, P. A.; van Loon, J. Th.; Sonneborn, G.; Sloan, G. C.; Skillman, E. D.; Meixner, M.; McDonald, I.; Jones, O. C.; Javadi, A.; Gehrz, R. D.; Britavskiy, N.; Bonanos, A. Z.
Referencia bibliográfica
The Astrophysical Journal, Volume 851, Issue 2, article id. 152, 14 pp. (2017).
Fecha de publicación:
12
2017
Revista
Número de citas
45
Número de citas referidas
31
Descripción
The survey for DUST in Nearby Galaxies with Spitzer (DUSTiNGS)
identified several candidate Asymptotic Giant Branch (AGB) stars in
nearby dwarf galaxies and showed that dust can form even in very
metal-poor systems ({\boldsymbol{Z}}∼ 0.008 {Z}ȯ ).
Here, we present a follow-up survey with WFC3/IR on the Hubble Space
Telescope (HST), using filters that are capable of distinguishing
carbon-rich (C-type) stars from oxygen-rich (M-type) stars: F127M,
F139M, and F153M. We include six star-forming DUSTiNGS galaxies (NGC
147, IC 10, Pegasus dIrr, Sextans B, Sextans A, and Sag DIG), all more
metal-poor than the Magellanic Clouds and spanning 1 dex in metallicity.
We double the number of dusty AGB stars known in these galaxies and find
that most are carbon rich. We also find 26 dusty M-type stars, mostly in
IC 10. Given the large dust excess and tight spatial distribution of
these M-type stars, they are most likely on the upper end of the AGB
mass range (stars undergoing Hot Bottom Burning). Theoretical models do
not predict significant dust production in metal-poor M-type stars, but
we see evidence for dust excess around M-type stars even in the most
metal-poor galaxies in our sample (12+{log}({{O}}/{{H}})=7.26{--}7.50).
The low metallicities and inferred high stellar masses (up to ∼10
{M}ȯ ) suggest that AGB stars can produce dust very
early in the evolution of galaxies (∼30 Myr after they form), and
may contribute significantly to the dust reservoirs seen in
high-redshift galaxies.
Based on observations made with the NASA/ESA Hubble Space Telescope at
the Space Telescope Science Institute, which is operated by the
Association of Universities for Research in Astronomy, Inc., under NASA
contract NAS 5-26555. These observations are associated with program
GO-14073.
Proyectos relacionados
Propiedades Físicas y Evolución de Estrellas Masivas
Las estrellas masivas son objetos claves para la Astrofísica. Estas estrellas nacen con más de 8 masas solares, lo que las condena a morir como Supernovas. Durante su rápida evolución liberan, a través de fuertes vientos estelares, gran cantidad de material procesado en su núcleo y, en determinadas fases evolutivas, emiten gran cantidad de
Sergio
Simón Díaz