INVESTIGADORES
CORSICO Alejandro Hugo
artículos
Título:
On the Challenging Variability of LS IV-14°116: Pulsational Instabilities Excited by the epsilon-Mechanism
Autor/es:
M. M. MILLER BERTOLAMI; A. H. CÓRSICO; L. G. ALTHAUS
Revista:
ASTROPHYSICAL JOURNAL
Editorial:
IOP PUBLISHING LTD
Referencias:
Año: 2011 vol. 741 p. 3 - 8
ISSN:
0004-637X
Resumen:
We investigate the pulsation driving mechanism responsible for the
long-period photometric variations observed in LS IV-14°116, a
subdwarf B star showing a He-enriched atmospheric composition. To this
end, we perform detailed nonadiabatic pulsation computations over fully
evolutionary post-He-core-flash stellar structure models, appropriate
for hot subdwarf stars at evolutionary phases previous to the He-core
burning stage. We found that the variability of LS IV-14°116 can be
attributed to non-radial g-mode pulsations excited by the
epsilon-mechanism acting in the He-burning shells that appear before the
star settles in the He-core burning stage. Even more interestingly, our
results show that LS IV-14°116 could be the first known pulsating
star in which the epsilon-mechanism of mode excitation is operating.
Last but not the least, we find that the period range of destabilized
modes is sensitive to the exact location of the burning shell, something
that might help in distinguishing between the different evolutionary
scenarios proposed for the formation of this star.