eCite Digital Repository

The ACS LCID Project: RR Lyrae Stars as Tracers of Old Population Gradients in the Isolated Dwarf Spheroidal Galaxy Tucana


Bernard, EJ and Gallart, C and Monelli, M and Aparicio, A and Cassisi, S and Skillman, ED and Stetson, PB and Cole, AA and Drozdovsky, I and Hidalgo, SL and Mateo, M and Tolstoy, E, The ACS LCID Project: RR Lyrae Stars as Tracers of Old Population Gradients in the Isolated Dwarf Spheroidal Galaxy Tucana, The Astrophysical Journal, 678, (1) pp. L21-L24. ISSN 0004-637X (2008) [Refereed Article]

Restricted - Request a copy

Copyright Statement

2008 The American Astronomical Society

Official URL:

DOI: doi:10.1086/588285


We present a study of the radial distribution of RR Lyrae variables, which present a range of photometric and pulsational properties, in the dwarf spheroidal galaxy Tucana. We find that the fainter RR Lyrae stars, having a shorter period, are more centrally concentrated than the more luminous, longer period RR Lyrae variables. Through comparison with the predictions of theoretical models of stellar evolution and stellar pulsation, we interpret the fainter RR Lyrae stars as a more metal-rich subsample. In addition, we show that they must be older than about 10 Gyr. Therefore, the metallicity gradient must have appeared very early on in the history of this galaxy. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with program 10505

Item Details

Item Type:Refereed Article
Keywords:galaxies: dwarf - galaxies: individual (Tucana) - Local Group - stars: horizontal-branch - stars: variables: other
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Cole, AA (Associate Professor Andrew Cole)
ID Code:52303
Year Published:2008
Web of Science® Times Cited:37
Deposited By:Physics
Deposited On:2008-06-17
Last Modified:2009-06-01

Repository Staff Only: item control page