Bibcode
Morrell, N. I.; Prieto, J. L.; García-Álvarez, D.; Mehner, A.; Bonanos, A. Z.; Britavskiy, N. E.
Bibliographical reference
Astronomy and Astrophysics, Volume 562, id.A75, 7 pp.
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2
2014
Journal
Citations
22
Refereed citations
20
Description
Context. 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. Aims: 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.
Methods: The method is based on mid-IR colors, using 3.6 μm and 4.5
μm 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.
Results: 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 μm and 4.5
μm.
Based on observations made with the Gran Telescopio Canarias (GTC),
installed in the Spanish Observatorio de El Roque de Los Muchachos of
the Instituto de Astrofísica de Canarias, on the island of La
Palma, and the 2.5 m du Pont telescope in operation at Las Campanas
Observatory, Chile.Spectra are only available at the CDS via anonymous
ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/562/A75
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Carlos
Allende Prieto