2001A&A...375..469K


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.16CEST16:15:23

2001A&A...375..469K - Astronomy and Astrophysics, volume 375, 469-475 (2001/8-4)

On the double-mode RR Lyrae variables of the Sculptor dwarf galaxy.

KOVACS G.

Abstract (from CDS):

Frequency analysis of more than 300 stars of the ogle database on Sculptor galaxy has led to the discovery of 18 double-mode RR Lyrae (RRd) variables. This yields a 20% incidence rate for double-mode pulsation among the variables previously classified as first overtone RR Lyrae stars in this galaxy. Most of the RRd stars cover the period range of 0.47d<P0<0.49d but there are two stars with longer periods of ≃0.54d. All variables fit well in the pattern of the P0->P1/P0 diagram, spanned by the RRd stars of the Galactic globular clusters and those of the Large Magellanic Cloud (LMC). It follows from our previous investigations that the luminosities and masses of the RRd stars in Galactic globular clusters and in the LMC are almost independent of metallicity. By assuming that the Sculptor RRd variables also obey this rule, with the aid of the pulsation equations we estimate their metallicities. For most of the stars we get [Fe/H]≃-1.5, which is the same value as that obtained from a semi-empirical method for the average metallicity of the fundamental mode (RRab) stars. Two RRd stars have considerably lower metallicities, but even those are within the range corresponding to the RRab stars. The narrower metallicity range of the RRd stars is in agreement with their observed luminosity range, which is about three times smaller than that of the RRab stars.

Abstract Copyright:

Journal keyword(s): stars: fundamental parameters - stars: variables: RR Lyr - stars: oscillations - stars: horizontal branch - globular clusters: - galaxies: individual: Sculptor dwarf spheroidal

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1116 4
2 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14838 1
3 M 68 GlC 12 39 27.98 -26 44 38.6   10.26 7.96     ~ 877 0
4 IC 4499 GlC 15 00 18.57 -82 12 49.6     8.56     ~ 310 0
5 M 15 GlC 21 29 58.33 +12 10 01.2   3       ~ 2908 0

    Equat.    Gal    SGal    Ecl

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2020.07.16-16:15:23

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