Blue straggler stars in dwarf spheroidal galaxies - II. Sculptor and Fornax

M. Mapelli, E. Ripamonti, G. Battaglia, E. Tolstoy, M. J. Irwin, B. Moore, S. Sigurdsson

Research output: Contribution to journalArticle

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Abstract

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.

Original languageEnglish (US)
Pages (from-to)1771-1782
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume396
Issue number3
DOIs
StatePublished - Jul 1 2009

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blue stars
dwarf galaxies
radial distribution
mass transfer
stars
distribution
star formation
history
simulation
horizontal branch stars
young

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Mapelli, M. ; Ripamonti, E. ; Battaglia, G. ; Tolstoy, E. ; Irwin, M. J. ; Moore, B. ; Sigurdsson, S. / Blue straggler stars in dwarf spheroidal galaxies - II. Sculptor and Fornax. In: Monthly Notices of the Royal Astronomical Society. 2009 ; Vol. 396, No. 3. pp. 1771-1782.
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Blue straggler stars in dwarf spheroidal galaxies - II. Sculptor and Fornax. / Mapelli, M.; Ripamonti, E.; Battaglia, G.; Tolstoy, E.; Irwin, M. J.; Moore, B.; Sigurdsson, S.

In: Monthly Notices of the Royal Astronomical Society, Vol. 396, No. 3, 01.07.2009, p. 1771-1782.

Research output: Contribution to journalArticle

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