Boyer, M. ; Whitelock, P. ; Sonneborn, G. ; Sloan, G. C. ; Skillman, E. D. ; Meixner, M. ; McQuinn, K. B. W. ; McDonald, I. ; Lagadec, E. ; Javadi, A. ; Groenewegen, M. A. T. ; Gehrz, R. D. ; Bonanos, A. Z.

published in Spitzer Proposal, pp. 11041 (2014)

Abstract: DUSTiNGS is a Spitzer Cycle 8 program that has provided the first complete spatially-resolved infrared census of evolved stars in a statistically significant sample of low metallicity, nearby (D1.5 Mpc) dwarf galaxies. One of the main results of the program to date is the discovery of hundreds of dust-producing AGB stars up to ~1 dex more metal-poor than previously known examples, suggesting that dust forms efficiently at least down to [Fe/H] = -2.2 dex. This discovery not only has implications for our interpretation of the interstellar medium and star formation in nearby, resolved galaxies, but also for our understanding of the dust production and chemical evolution of galaxies in the metal-poor environment of the early Universe. Here, we propose new, multi-epoch IRAC observations of 10 DUSTiNGS galaxies to measure the amplitudes, periods, and dust excesses of the DUSTiNGS AGB stars and thereby gain insight into the basic properties of the underlying dust producing populations. These data will provide a foundation for understanding dust production by AGB stars in chemically un-evolved systems, as well as providing a target list of these enigmatic objects for James Webb Space Telescope (JWST) follow-up.

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