Heavy-metal enrichment in the intermediate He-sdOB pulsator Feige 46. (arXiv:1908.04587v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Latour_M/0/1/0/all/0/1">Marilyn Latour</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dorsch_M/0/1/0/all/0/1">Matti Dorsch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heber_U/0/1/0/all/0/1">Ulrich Heber</a>
The intermediate He-enriched hot subdwarf star Feige 46 was recently reported
as the second member of the V366 Aqr (or He-sdOBV) pulsating class. Feige 46 is
very similar to the prototype of the class, LS IV$-$14116, not only in terms of
pulsational properties, but also in terms of atmospheric parameters and
kinematic properties. LS IV$-$14116 is additionally characterized by a very
peculiar chemical composition, with extreme overabundances of the trans-iron
elements Ge, Sr, Y, and Zr. In this paper, we investigate the possibility that
the similitude between both pulsators extends to their chemical composition. We
retrieved archived optical and UV spectroscopic observations of Feige 46 and
perform an abundance analysis using model atmospheres and synthetic spectra
computed with TLUSTY and SYNSPEC. In total, we derive abundances for 16
metallic elements and provide upper limits for four additional elements. From
absorption lines in the optical spectrum of the star we measure an enrichment
of more than 10 000$times$ solar for yttrium and zirconium. As for strontium,
the UV spectrum revealed it to be equally enriched. Our results confirm that
Feige 46 is not only a member of the now growing group of “heavy-metal”
subdwarfs, but also has an abundance pattern remarkably similar to that of LS
IV$-$14116.
The intermediate He-enriched hot subdwarf star Feige 46 was recently reported
as the second member of the V366 Aqr (or He-sdOBV) pulsating class. Feige 46 is
very similar to the prototype of the class, LS IV$-$14116, not only in terms of
pulsational properties, but also in terms of atmospheric parameters and
kinematic properties. LS IV$-$14116 is additionally characterized by a very
peculiar chemical composition, with extreme overabundances of the trans-iron
elements Ge, Sr, Y, and Zr. In this paper, we investigate the possibility that
the similitude between both pulsators extends to their chemical composition. We
retrieved archived optical and UV spectroscopic observations of Feige 46 and
perform an abundance analysis using model atmospheres and synthetic spectra
computed with TLUSTY and SYNSPEC. In total, we derive abundances for 16
metallic elements and provide upper limits for four additional elements. From
absorption lines in the optical spectrum of the star we measure an enrichment
of more than 10 000$times$ solar for yttrium and zirconium. As for strontium,
the UV spectrum revealed it to be equally enriched. Our results confirm that
Feige 46 is not only a member of the now growing group of “heavy-metal”
subdwarfs, but also has an abundance pattern remarkably similar to that of LS
IV$-$14116.
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