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We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to…

Solar and Stellar Astrophysics · Physics 2024-05-06 L. R. Bedin , D. Nardiello , M. Salaris , M. Libralato , P. Bergeron , A. J. Burgasser , D. Apai , M. Griggio , M. Scalco , J. Anderson , R. Gerasimov , A. Bellini

We present the CMD from deep HST imaging in the globular cluster NGC 6397. The ACS was used for 126 orbits to image a single field in two colors (F814W, F606W) 5 arcmin SE of the cluster center. The field observed overlaps that of archival…

The majority of the inhomogeneities in the chemical composition of Globular Cluster (GC) stars appear due to primordial enrichment by hot-CNO cycled material processed in stars belonging to a first stellar generation. Either massive AGB…

Astrophysics · Physics 2009-11-13 F. D'Antona , V. Caloi

There is a growing body of evidence for the presence of multiple stellar populations in some globular clusters, including NGC 1851. For most of these peculiar globular clusters, however, the evidence for the multiple red giant-branches…

Astrophysics of Galaxies · Physics 2014-11-20 Sang-Il Han , Young-Wook Lee , Seok-Joo Joo , Sangmo Tony Sohn , Suk-Jin Yoon , Hak-Sub Kim , Jae-Woo Lee

We present the first evidence of multiple populations in the Galactic globular cluster NGC 6362. We used optical and near-UV Hubble Space Telescope and ground based photometry, finding that both the sub giant and red giant branches are…

Solar and Stellar Astrophysics · Physics 2015-06-22 E. Dalessandro , D. Massari , M. Bellazzini , P. Miocchi , A. Mucciarelli , M. Salaris , S. Cassisi , F. R. Ferraro , B. Lanzoni

We obtained FLAMES GIRAFFE+UVES spectra for both first and second-generation red giant branch (RGB) stars in the globular cluster (GC) NGC 362 and used them to derive abundances of 21 atomic species for a sample of 92 stars. The surveyed…

Astrophysics of Galaxies · Physics 2015-06-16 E. Carretta , A. Bragaglia , R. G. Gratton , S. Lucatello , V. D'Orazi , M. Bellazzini , G. Catanzaro , F. Leone , Y. Momany , A. Sollima

Information on globular clusters (GC) formation mechanisms can be gathered by studying the chemical signature of the multiple populations that compose these stellar systems. In particular, we are investigating the anticorrelations among O,…

Solar and Stellar Astrophysics · Physics 2015-11-04 A. Bragaglia , E. Carretta , A. Sollima , P. Donati , V. D'Orazi , R. G. Gratton , S. Lucatello , C. Sneden

We exploit the large number of archival HST images of 47 Tuc to examine its subgiant branch (SGB) and main sequence (MS) for signs of multiple populations. In the cluster core, we find that the cluster's SGB exhibits a clear spread in…

Astrophysics of Galaxies · Physics 2010-01-15 J. Anderson , G. Piotto , I. R. King , L. R. Bedin , P. Guhathakurta

We present results of a study of the central regions of NGC 6397 using Hubble Space Telescope's Advanced Camera for Surveys, focusing on a group of 24 faint blue stars that form a sequence parallel to, but brighter than, the more populated…

Astrophysics of Galaxies · Physics 2011-02-11 R. R. Strickler , A. M. Cool , J. Anderson , H. N. Cohn , P. M. Lugger , A. M. Serenelli

We report the presence of two distinct red giant branches (RGBs) in the globular cluster NGC 288 from the narrow-band calcium and Str\"{o}mgren b & y photometry obtained at the CTIO 4m Blanco telescope. The RGB of NGC 288 is clearly split…

Astrophysics of Galaxies · Physics 2015-05-28 Dong-Goo Roh , Young-Wook Lee , Seok-Joo Joo , Sang-Il Han , Young-Jong Sohn , Jae-Woo Lee

We present chemical abundances in three red giants and two turn-off stars in the metal poor Galactic globular cluster (GC) NGC 6397 based on spectroscopy obtained with the MIKE high resolution spectrograph on the Magellan 6.5-m Clay…

Astrophysics of Galaxies · Physics 2015-05-28 Andreas Koch , Andrew McWilliam

AIMS. We present abundance analysis based on high resolution spectra of 105 isolated red giant branch (RGB) stars in the Galactic Globular Cluster NGC 6121 (M4). Our aim is to study its star population in the context of the multi-population…

Astrophysics · Physics 2009-11-13 A. F. Marino , S. Villanova , G. Piotto , A. P. Milone , Y. Momany , L. R. Bedin , A. M. Medling

We present the first results from the analysis of GIRAFFE spectra of more than 1200 red giants stars in 19 Galactic Globular Clusters (GCs), to study the chemical composition of second generation stars and their link with global cluster…

Astrophysics · Physics 2008-11-24 Eugenio Carretta , Angela Bragaglia , Raffaele G. Gratton , Sara Lucatello

The full stellar population of NGC 6334, one of the most spectacular regions of massive star formation in the nearby Galaxy, have not been well-sampled in past studies. We analyze here a mosaic of two Chandra X-ray Observatory images of the…

Astrophysics of Galaxies · Physics 2015-05-13 Eric D. Feigelson , Amanda L. Martin , Collin J. McNeill , Patrick S. Broos , Gordon P. Garmire

We exploit multi-band Hubble Space Telescope photometry to investigate multiple populations (MPs) along the red horizontal branches (HBs) and red clumps of fourteen metal-rich Globular Clusters (GCs), including twelve Milky Way GCs and the…

We present N-body models to complement deep imaging of the metal-poor core-collapsed cluster NGC6397 obtained with the Hubble Space Telescope. All simulations include stellar and binary evolution in-step with the stellar dynamics and…

In the last years, photometric and spectroscopic evidence has demonstrated that many, maybe all the Globular Clusters (GC) host multiple stellar populations. High-resolution spectroscopy has established that, while most GCs are…

Solar and Stellar Astrophysics · Physics 2011-07-13 A. P. Milone , G. Piotto , R. L. Bedin , A. F. Marino , Y. Momany , S. Villanova

In this paper we present a multi-wavelength analysis of the complex stellar populations within the massive globular cluster Mayall II (G1), a satellite of the nearby Andromeda galaxy projected at a distance of 40 kpc. We used images…

Solar and Stellar Astrophysics · Physics 2019-03-13 D. Nardiello , G. Piotto , A. P. Milone , R. M. Rich , S. Cassisi , L. R. Bedin , A. Bellini , A. Renzini

In this study, we present a detailed study of mass segregation in the globular clister NGC 6397. First, we carry out a photometric analysis of projected ESO-VLT data (between 1 and 10 arcmin from the cluster centre), presenting the…

Solar and Stellar Astrophysics · Physics 2014-11-25 E. Martinazzi , A. Pieres , S. O. Kepler , J. E. S. Costa , C. Bonatto , E. Bica

Most Globular Clusters (GC) show chemical inhomogeneities in the composition of their stars, apparently due to a second stellar generation (SG) in which the forming gas is enriched by hot-CNO cycled material processed in stars belonging to…

Astrophysics · Physics 2009-11-13 F. D'Antona , V. Caloi