2008ApJ...678L..21B

Query : 2008ApJ...678L..21B

2008ApJ...678L..21B - Astrophys. J., 678, L21-L24 (2008/May-1)

The ACS LCID project: RR Lyrae stars as tracers of old population gradients in the isolated dwarf spheroidal galaxy Tucana.

BERNARD E.J., GALLART C., MONELLI M., APARICIO A., CASSISI S., SKILLMAN E.D., STETSON P.B., COLE A.A., DROZDOVSKY I., HIDALGO S.L., MATEO M. and TOLSTOY E.

Abstract (from CDS):

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.

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Journal keyword(s): Galaxies: Dwarf - galaxies: individual (Tucana) - Galaxies: Local Group - Stars: Horizontal-Branch - Stars: Variables: Other

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
2 NAME Tuc Galaxy G 22 41 49.6 -64 25 10   15.7 15.2     ~ 324 0
3 NAME Local Group GrG ~ ~           ~ 9325 0

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