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Photometry with HST's ACS reveals that the subgiant branch (SGB) of the globular cluster NGC 1851 splits into two well-defined branches. If the split is due only to an age effect, the two SGBs would imply two star formation episodes…

Ancient Galactic Globular Clusters (GCs) have long fascinated astronomers due to their intriguing multiple stellar populations characterized by variations in light-element abundances. Among these clusters, Type-II GCs stand out as they…

We derived chemical abundances for C, N, O, Na, Mg and Al in 20 asymptotic giant branch (AGB) stars in the globular cluster NGC 6752. All these elements (but Mg) show intrinsic star-to-star variations and statistically significant…

Solar and Stellar Astrophysics · Physics 2016-07-20 E. Lapenna , C. Lardo , A. Mucciarelli , M. Salaris , F. R. Ferraro , B. Lanzoni , D. Massari , P. B. Stetson , S. Cassisi , A. Savino

Globular clusters (GCs) are key to understanding the formation and evolution of our Galaxy. While the abundances of light and Fe-peak elements in GCs have been widely studied, investigations into heavier, neutron-capture elements -- and…

Multiple populations revealed in globular clusters (GCs) are important windows to the formation and evolution of these stellar systems. The metal-rich GCs in the Galactic bulge are an indispensable part of this picture, but the high optical…

We used the UVES spectrograph on Kueyen (VLT UT2) to perform the abundance analysis of stars at the base of the giant branch (RGB) and at the main sequence turn-off in the globular cluster 47 Tuc (NGC 104). High dispersion spectra (R ~…

Globular clusters (GCs) are the oldest stellar systems in the Milky Way. Long time considered as simple stellar populations, nowadays we recognize their complex star formation history through precise abundance analysis of a variety of…

Astrophysics of Galaxies · Physics 2015-06-05 Nikolay Kacharov , Andreas Koch

We present the first measure of Fe and Na abundances in NGC 6362, a low-mass globular cluster where first and second generation stars are fully spatially mixed. A total of 160 member stars (along the red giant branch and the red horizontal…

Solar and Stellar Astrophysics · Physics 2016-06-22 A. Mucciarelli , E. Dalessandro , D. Massari , M. Bellazzini , F. R. Ferraro , B. Lanzoni , C. Lardo , M. Salaris , S. Cassisi

The analysis of multiple populations (MPs) in globular clusters (GCs) has become a forefront area of research in astronomy. Multiple red giant branches (RGBs), subgiant branches (SGBs), and even main sequences (MSs) have now been observed…

Solar and Stellar Astrophysics · Physics 2015-06-19 Jeffrey D. Cummings , D. Geisler , S. Villanova , G. Carraro

Large star-to-star abundance variations are direct evidence of multiple stellar populations in Galactic globular clusters (GCs). The main and most widespread chemical signature is the anti-correlation of the stellar Na and O abundances. The…

Solar and Stellar Astrophysics · Physics 2019-04-10 Eugenio Carretta

We present chemical abundances for 17 elements in a sample of 11 red giant branch stars in NGC 6362 from UVES spectra. NGC 6362 is one of the least massive globulars where multiple populations have been detected, yet its detailed chemical…

Solar and Stellar Astrophysics · Physics 2017-04-12 D. Massari , A. Mucciarelli , E. Dalessandro , M. Bellazzini , S. Cassisi , G. Fiorentino , R. A. Ibata , C. Lardo , M. Salaris

We observed a sample of 90 red giant branch (RGB) stars in NGC 2808 using FLAMES/GIRAFFE and the high resolution grating with the set up HR21. These stars have previous accurate atmospheric parameters and abundances of light elements. We…

Solar and Stellar Astrophysics · Physics 2018-07-11 Eugenio Carretta , Angela Bragaglia , Sara Lucatello , Raffaele G. Gratton , Valentina D'Orazi , Antonio Sollima

NGC 4833 is a metal-poor Galactic globular cluster (GC) whose multiple stellar populations present an extreme chemical composition. The Na-O anti-correlation is quite extended, which is in agreement with the long tail on the blue horizontal…

Solar and Stellar Astrophysics · Physics 2021-06-02 Eugenio Carretta

The presence of Multiple Stellar Populations (MSPs) in Galactic Globular Clusters (GCs) is a poorly understood phenomenon. By probing different spectral ranges that are affected by different absorption lines using the multi-band photometric…

Almost all globular clusters investigated exhibit a spread in their light element abundances, the most studied being a Na:O anticorrelation. In contrast, open clusters show a homogeneous composition and are still regarded as Simple Stellar…

Astrophysics of Galaxies · Physics 2015-06-05 D. Geisler , S. Villanova , G. Carraro , C. Pilachowski , J. Cummings , C. I. Johnson , F. Bresolin

The globular cluster M 2 has a photometrically detected double red giant branch (RGB) sequence. We investigate here the chemical differences between the two RGBs in order to gain insight in the star formation history of this cluster. The…

Solar and Stellar Astrophysics · Physics 2015-06-15 C. Lardo , E. Pancino , A. Mucciarelli , M. Bellazzini , M. Rejkuba , S. Marinoni , G. Cocozza , G. Altavilla , S. Ragaini

It is widely accepted that individual Galactic globular clusters harbor two coeval generations of stars, the first one born with the `standard' alpha-enhanced metal mixture observed in field Halo objects, the second one characterized by an…

Astrophysics of Galaxies · Physics 2012-03-21 Paula Coelho , Susan Percival , Maurizio Salaris

Almost several decades after the discovery of the first multiple populations in galactic globular clusters (GC) the debate on their formation is still extremely current and NGC2808 remains one of the best benchmark to test any scenario for…

Solar and Stellar Astrophysics · Physics 2018-07-18 Marcella Di Criscienzo , Paolo Ventura , Francesca D'Antona , Flavia Dell'Agli , Marco Tailo

Detailed chemical abundances of two stars in the intermediate-age Large Magellanic Cloud (LMC) globular cluster NGC~1718 are presented, based on high resolution spectroscopic observations with the MIKE spectrograph. The detailed abundances…

Astrophysics of Galaxies · Physics 2017-02-12 Charli Sakari , Andrew McWilliam , George Wallerstein

We derive the first detailed chemical abundances of three star clusters in the Large Magellanic Cloud (LMC), NGC1831 (436+/-22 Myr), NGC1856 (350+/-18 Myr) and [SL63]268 (1230+/-62 Myr) using integrated-light spectroscopic observations…

Astrophysics of Galaxies · Physics 2022-05-11 Randa Asa'd , S. Hernandez , A. M. As'ad , M. Molero , F. Matteucci , S. Larsen , Igor V. Chilingarian