The role of episodic mass loss in massive star evolution is one of the most
important open questions of current stellar evolution theory. Episodic mass
loss produces dust and therefore causes evolved massive stars to be very
luminous in the mid-infrared and dim at optical wavelengths. We aim to increase
the number of investigated luminous mid-IR sources to shed light on the late
stages of these objects. To achieve this we employed mid-IR selection criteria
to identity dusty evolved massive stars in two nearby galaxies. The method is
based on mid-IR colors, using 3.6 {\mu}m and 4.5 {\mu}m photometry from
archival Spitzer Space Telescope images of nearby galaxies and J-band
photometry from 2MASS. We applied our criteria to two nearby star-forming dwarf
irregular galaxies, Sextans A and IC 1613, selecting eight targets, which we
followed up with spectroscopy. Our spectral classification and analysis yielded
the discovery of two M-type supergiants in IC 1613, three K-type supergiants
and one candidate F-type giant in Sextans A, and two foreground M giants. We
show that the proposed criteria provide an independent way for identifying
dusty evolved massive stars, that can be extended to all nearby galaxies with
available Spitzer/IRAC images at 3.6 {\mu}m and 4.5 {\mu}m.Comment: 8 pages, 4 figures, A&A in pres
