Browsing by Author "Kacharov, N."

Now showing 1 - 5 of 5
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    A study of rotating globular clusters : the case of the old metal-poor globular cluster NGC 4372
    (2014) Kacharov, N.; Bianchini, P.; Koch, A.; Frank, M. J.; Martin, N. F.; Ven G., van de; Puzia, Thomas H.; McDonald, I.; Johnson, C. I.; Zijlstra, A. A.
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    Galactic evolution of sulphur as traced by globular clusters
    (EDP SCIENCES S A, 2015) Kacharov, N.; Koch, A.; Caffau, E.; Sbordone, L.
    Context. Sulphur is an important volatile a element, but its role in the Galactic chemical evolution is still uncertain, and more observations constraining the sulphur abundance in stellar photospheres are required.
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    Stellar chemo-kinematics of the Cetus dwarf spheroidal galaxy
    (2018) Taibi, S.; Battaglia, G.; Kacharov, N.; Rejkuba, M.; Irwin, M.; Leaman, R.; Zoccali, Manuela; Tolstoy, E.; Jablonka, P.
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    The Gaia-ESO Survey: Detailed abundances in the metal-poor globular cluster NGC 4372
    (EDP SCIENCES S A, 2015) San Roman, I.; Munoz, C.; Geisler, D.; Villanova, S.; Kacharov, N.; Koch, A.; Carraro, G.; Tautvaisiene, G.; Vallenari, A.; Alfaro, E. J.; Bensby, T.; Flaccomio, E.; Francois, P.; Korn, A. J.; Pancino, E.; Recio Blanco, A.; Smiljanic, R.; Bergemann, M.; Costado, M. T.; Damiani, F.; Heiter, U.; Hourihane, A.; Jofre, P.; Lardo, C.; de Laverny, P.; Masseron, T.; Morbidelli, L.; Sbordone, L.; Sousa, S. G.; Worley, C. C.; Zaggia, S.
    We present the abundance analysis for a sample of 7 red giant branch stars in the metal-poor globular cluster NGC 4372 based on UVES spectra acquired as part of the Gaia-ESO Survey. This is the first extensive study of this cluster from high-resolution spectroscopy. We derive abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, Fe, Cr, Ni, Y, Ba, and La. We find a metallicity of [Fe/H] = -2.19 +/- 0.03 and find no evidence of any metallicity spread. This metallicity makes NGC 4372 one of the most metal-poor Galactic globular clusters. We also find an a-enhancement typical of halo globular clusters at this metallicity. Significant spreads are observed in the abundances of light elements. In particular, we find a Na-O anticorrelation. Abundances of O are relatively high compared with other globular clusters. This could indicate that NGC 4372 was formed in an environment with high O for its metallicity. A Mg-Al spread is also present that spans a range of more than 0.5 dex in Al abundances. Na is correlated with Al and Mg abundances at a lower significance level. This pattern suggests that the Mg-Al burning cycle is active. This behavior can also be seen in giant stars of other massive, metal-poor clusters. A relation between light and heavy s-process elements has been identified.
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    The Tucana dwarf spheroidal galaxy : not such a massive failure after all
    (2020) Taibi, S.; Battaglia, G.; Rejkuba, M.; Leaman, R.; Kacharov, N.; Iorio, G.; Jablonka, P.; Zoccali, Manuela