Discovery of stars surrounded by iron dust in the LMC. (arXiv:1901.03621v1 [astro-ph.SR])

Discovery of stars surrounded by iron dust in the LMC. (arXiv:1901.03621v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Marini_E/0/1/0/all/0/1">E. Marini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+DellAgli_F/0/1/0/all/0/1">F. Dell&#x27;Agli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Criscienzo_M/0/1/0/all/0/1">M. Di Criscienzo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Puccetti_S/0/1/0/all/0/1">S. Puccetti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garcia_Hernandez_D/0/1/0/all/0/1">D. A. Garc&#xed;a-Hern&#xe1;ndez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mattsson_L/0/1/0/all/0/1">L. Mattsson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ventura_P/0/1/0/all/0/1">P. Ventura</a>

We consider a small sample of oxygen-rich, asymptotic giant branch stars in
the Large Magellanic Cloud, observed by the Spitzer Space Telescope, exhibiting
a peculiar spectral energy distribution, which can be hardly explained by the
common assumption that dust around AGB stars is primarily composed of silicate
grains. We suggest that this uncommon class of objects are the progeny of a
metal-poor generation of stars, with metallicity $Z sim 1-2times 10^{-3}$,
formed $sim 100$ Myr ago. The main dust component in the circumstellar
envelope is solid iron. In these stars the poor formation of silicates is set
by the strong nucleosynthesis experienced at the base of the envelope, which
provokes a scarcity of magnesium atoms and water molecules, required to the
silicate formation. The importance of the present results to interpret the data
from the incoming James Webb Space Telescope is also discussed.

We consider a small sample of oxygen-rich, asymptotic giant branch stars in
the Large Magellanic Cloud, observed by the Spitzer Space Telescope, exhibiting
a peculiar spectral energy distribution, which can be hardly explained by the
common assumption that dust around AGB stars is primarily composed of silicate
grains. We suggest that this uncommon class of objects are the progeny of a
metal-poor generation of stars, with metallicity $Z sim 1-2times 10^{-3}$,
formed $sim 100$ Myr ago. The main dust component in the circumstellar
envelope is solid iron. In these stars the poor formation of silicates is set
by the strong nucleosynthesis experienced at the base of the envelope, which
provokes a scarcity of magnesium atoms and water molecules, required to the
silicate formation. The importance of the present results to interpret the data
from the incoming James Webb Space Telescope is also discussed.

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