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 split in two parallel sequences in all color-magnitude diagrams where the F336W filter (or U band) is used. This cluster is one of the least massive globulars (M tot ~ 5 × 104 M ⊙) where multiple populations have been detected so far. Even more interestingly and at odds with any previous finding, we observe that the two identified populations share the same radial distribution across the cluster extension. NGC 6362 is the first system where stars from different populations are found to be completely spatially mixed. Based on N-body and hydrodynamical simulations of multiple stellar generations, we argue that to reproduce these findings NGC 6362 should have lost up to 80% of its original mass.
FIRST EVIDENCE OF FULLY SPATIALLY MIXED FIRST AND SECOND GENERATIONS IN GLOBULAR CLUSTERS: THE CASE OF NGC 6362 / Emanuele Dalessandro;Davide Massari;Michele Bellazzini;Paolo Miocchi;Alessio Mucciarelli;Maurizio Salaris;Santi Cassisi;Francesco R. Ferraro;Barbara Lanzoni. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 791:(2014), pp. L4-L8. [10.1088/2041-8205/791/1/L4]
FIRST EVIDENCE OF FULLY SPATIALLY MIXED FIRST AND SECOND GENERATIONS IN GLOBULAR CLUSTERS: THE CASE OF NGC 6362
DALESSANDRO, EMANUELE;MASSARI, DAVIDE;MIOCCHI, PAOLO;MUCCIARELLI, ALESSIO;FERRARO, FRANCESCO ROSARIO;LANZONI, BARBARA
2014
Abstract
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 split in two parallel sequences in all color-magnitude diagrams where the F336W filter (or U band) is used. This cluster is one of the least massive globulars (M tot ~ 5 × 104 M ⊙) where multiple populations have been detected so far. Even more interestingly and at odds with any previous finding, we observe that the two identified populations share the same radial distribution across the cluster extension. NGC 6362 is the first system where stars from different populations are found to be completely spatially mixed. Based on N-body and hydrodynamical simulations of multiple stellar generations, we argue that to reproduce these findings NGC 6362 should have lost up to 80% of its original mass.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
