Bibcode
Mapelli, M.; Ripamonti, E.; Battaglia, G.; Tolstoy, E.; Irwin, M. J.; Moore, B.; Sigurdsson, S.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 396, Issue 3, pp. 1771-1782.
Fecha de publicación:
7
2009
Número de citas
55
Número de citas referidas
43
Descripción
The existence of blue straggler stars (BSSs) in dwarf spheroidal
galaxies (dSphs) is still an open question. In fact, many BSS candidates
have been observed in the Local Group dSphs, but it is unclear whether
they are real BSSs or young stars. Shedding light on the nature of these
BSS candidates is crucial in order to understand the star formation
history of dSphs. In this paper, we consider BSS candidates in Sculptor
and Fornax. In Fornax, there are strong hints that the BSS population is
contaminated by young stars, whereas in Sculptor there is no clear
evidence of recent star formation. We derive the radial and luminosity
distribution of BSS candidates from wide field imaging data extending
beyond the nominal tidal radius of these galaxies. The observations are
compared with the radial distribution of BSSs expected from dynamical
simulations. In Sculptor, the radial distribution of BSS candidates is
consistent with that of red horizontal branch (RHB) stars and is in
agreement with theoretical expectations for BSSs generated via mass
transfer in binaries. On the contrary, in Fornax, the radial
distribution of BSS candidates is more concentrated than that of all the
considered stellar populations. This result supports the hypothesis that
most of BSS candidates in Fornax are young stars, and this is consistent
with previous studies.