Utilizza questo identificativo per citare o creare un link a questo documento:
http://hdl.handle.net/20.500.12386/34390
Titolo: | Spectroscopy and photometry of the least-massive Type-II globular clusters: NGC1261 AND NGC6934 | Autori: | MARINO, Anna Milone, A. P. Renzini, A. Yong, D. Asplund, M. Da Costa, G. S. Jerjen, H. Cordoni, G. Carlos,M. Dondoglio, E. Lagioia, E. P. Jang, S. Tailo, M. |
Data pubblicazione: | 2021 | Rivista: | THE ASTROPHYSICAL JOURNAL | Numero: | 923 | Fascicolo: | 1 | Da pagina:: | 22 | Abstract: | Recent work has revealed two classes of Globular Clusters (GCs), dubbed Type-I and Type-II. Type-II GCs are characterized by a blue- and a red- red giant branch composed of stars with different metallicities, often coupled with distinct abundances in the slow-neutron capture elements (s-elements). Here we continue the chemical tagging of Type-II GCs by adding the two least-massive clusters of this class, NGC1261 and NGC6934. Based on both spectroscopy and photometry, we find that red stars in NGC1261 are slightly enhanced in [Fe/H] by ~0.1 dex and confirm that red stars of NGC 6934 are enhanced in iron by ~0.2 dex. Neither NGC1261 nor NGC6934 show internal variations in the s-elements, which suggests a GC mass threshold for the occurrence of s-process enrichment. We found a significant correlation between the additional Fe locked in the red stars of Type-II GCs and the present-day mass of the cluster. Nevertheless, most Type II GCs retained a small fraction of Fe produced by SNe II, lower than the 2%; NGC6273, M54 and omega Centauri are remarkable exceptions. In the appendix, we infer for the first time chemical abundances of Lanthanum, assumed as representative of the s-elements, in M54, the GC located in the nucleus of the Sagittarius dwarf galaxy. Red-sequence stars are marginally enhanced in [La/Fe] by 0.10\pm0.06 dex, in contrast with the large [La/Fe] spread of most Type II GCs. We suggest that different processes are responsible for the enrichment in iron and s-elements in Type-II GCs. | URI: | http://hdl.handle.net/20.500.12386/34390 | URL: | https://iopscience.iop.org/article/10.3847/1538-4357/ac282c http://arxiv.org/abs/2106.15978v1 |
ISSN: | 0004-637X | DOI: | 10.3847/1538-4357/ac282c | Fulltext: | open |
È visualizzato nelle collezioni: | 1.01 Articoli in rivista |
File in questo documento:
File | Descrizione | Dimensioni | Formato | |
---|---|---|---|---|
Marino_2021_ApJ_923_22.pdf | PDF editoriale | 1.96 MB | Adobe PDF | Visualizza/apri |
Page view(s)
13
controllato il 4-ago-2024
Download(s)
7
controllato il 4-ago-2024
Google ScholarTM
Check
Altmetric
Altmetric
Tutti i documenti in DSpace sono pubblicati ad Accesso Aperto, salvo diversa indicazione per alcuni documenti specifici.