CARBON IN RED GIANTS IN GLOBULAR CLUSTERS AND DWARF SPHEROIDAL GALAXIES

Interest in dwarf spheroidal galaxies is motivated by a number of reasons; an important one on the occasion of this colloquium is the abundance of variable stars. The theory of stellar evolution and stellar pulsations is now able to predict from theoretical considerations characteristic properties of variable stars in the colour-magnitude diagram (Iben, 1971). By observing the variable stars in the field, and in as wide a selection of objects as possible, more insight can be obtained into the history of the oldest members of our Galaxy (the globular clusters) and of the dwarf spheroidal galaxies in the Local Group. It is worthwhile to explore the spheroidal galaxies as observational tests for the theoretical predictions of conditions in space away from our Galaxy. The numbers of variable stars in the dwarf spheroidal galaxies are such that we may expect well-defined relations to emerge once reliable magnitude sequences have been set up, the variable stars found, and their periods determined. Six dwarf spheroidal galaxies are presently known in the Local Group within a distance of 250 kpc. In Table I, which lists members of the Local Group, they are at the low-luminosity end of the sequence of elliptical galaxies (van den Bergh, 1968).

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The Chemical Abundances of the Halo Clusters of the Galaxy

Symposium - International Astronomical Union ◽

10.1017/s0074180900145504 ◽

1978 ◽

Vol 80 ◽

pp. 177-182

Author(s):

R. Canterna ◽

R. A. Schommer

Keyword(s):

Globular Clusters ◽

Broad Band ◽

Mean Value ◽

Red Giants ◽

Galactocentric Distance ◽

Chemical Abundances ◽

Dwarf Spheroidal Galaxies ◽

The Galaxy ◽

Ursa Minor ◽

Metal Abundances

Photometric metal abundances of individual red giants in eight extremely distant halo globular clusters and the Draco and Ursa Minor dwarf spheroidal galaxies have been obtained using the Washington broad-band system, C, M, T1, T2(Canterna 1976). Observations were made at the KPNO 2.1-m and CTIO 1.5-m telescopes. In Table I we list for each system the mean value of [Fe/H], the number of stars observed in each system, n, the Galactocentric distance, RGC, the intrinsic color of the giant branch at the level of the horizontal branch (HB), (B-V)o,g, and the fraction of HB stars bluer than the RR Lyrae gap, fB. Sources for unpublished color-magnitude diagram (CMD) data are: Pal 11 (Canterna and Schommer), Pal 12 (Canterna and Harris), and Ursa Minor (Schommer, Olszewski and Kunkel).

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DISCOVERY OF SUPER-Li-RICH RED GIANTS IN DWARF SPHEROIDAL GALAXIES

The Astrophysical Journal ◽

10.1088/2041-8205/752/1/l16 ◽

2012 ◽

Vol 752 (1) ◽

pp. L16 ◽

Cited By ~ 26

Author(s):

Evan N. Kirby ◽

Xiaoting Fu ◽

Puragra Guhathakurta ◽

Licai Deng

Keyword(s):

Red Giants ◽

Dwarf Spheroidal Galaxies ◽

Spheroidal Galaxies

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Population gradients in dwarf spheroidal galaxies KKs 3 and ESO 269-66

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318005550 ◽

2018 ◽

Vol 14 (S344) ◽

pp. 420-421

Author(s):

M. E. Sharina ◽

L. N. Makarova ◽

D. I. Makarov

Keyword(s):

Surface Density ◽

Globular Clusters ◽

Stellar Populations ◽

Density Profiles ◽

Dwarf Spheroidal Galaxies ◽

Star Forming ◽

Central Regions ◽

Low Metallicity ◽

High Metallicity ◽

Spheroidal Galaxies

AbstractWe compare the properties of stellar populations for globular clusters (GCs) and field stars in two dwarf spheroidal galaxies (dSphs): ESO269-66, a close neighbour of NGC5128, and KKs3, one of the few isolated dSphs within 10 Mpc. We analyse the surface density profiles of low and high metallicity (blue and red) stars in two galaxies using the Sersic law. We argue that 1) the density profiles of red stars are steeper than those of blue stars, which evidences in favour of the metallicity and age gradients in dSphs; 2) globular clusters in KKs3 and ESO 269-66 contain 4 and 40 percent of all stars with [Fe / H] ~ 1.6 dex and the age of 12 Gyr, correspondingly. Therefore, GCs are relics of the first powerful star-forming bursts in the central regions of the galaxies. KKs 3 has lost a smaller percentage of old low-metallicity stars than ESO269-66, probably, thanks to its isolation.

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