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.
Bibliographical reference
The Astrophysical Journal, Volume 851, Issue 2, article id. 152, 14 pp. (2017).
Advertised on:
12
2017
Journal
Citations
45
Refereed citations
31
Description
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.
Related projects
Physical properties and evolution of Massive Stars
This project aims at the searching, observation and analysis of massive stars in nearby galaxies to provide a solid empirical ground to understand their physical properties as a function of those key parameters that gobern their evolution (i.e. mass, spin, metallicity, mass loss, and binary interaction). Massive stars are central objects to
Sergio
Simón Díaz