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

journal contribution
posted on 2023-05-16, 21:49 authored by Bernard, EJ, Gallart, C, Monelli, M, Aparicio, A, Cassisi, S, Skillman, ED, Stetson, PB, Andrew ColeAndrew Cole, Drozdovsky, I, Hidalgo, SL, Mateo, M, Tolstoy, E
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

History

Publication title

The Astrophysical Journal

Volume

678

Pagination

L21-L24

ISSN

0004-637X

Department/School

School of Natural Sciences

Publisher

University of Chicago Press

Place of publication

Chicago, USA

Rights statement

© 2008 The American Astronomical Society

Repository Status

  • Restricted

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Expanding knowledge in the physical sciences

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