Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2011-04-08
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
Accepted for publication in ApJ
Scientific paper
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 anticorrelated CN-ONa abundance pattern overimposed on the first generation, $\alpha$-enhanced metal mixture. We have investigated with appropriate stellar population synthesis models how this second generation of stars affects the integrated spectrum of a typical metal rich Galactic globular cluster, like 47\,Tuc, focusing our analysis on the widely used Lick-type indices. We find that the only indices appreciably affected by the abundance anticorrelations are Ca4227, G4300, ${\rm CN_1}$, ${\rm CN_2}$ and NaD. The age-sensitive Balmer line, Fe line and the [MgFe] indices widely used to determine age, Fe and total metallicity of extragalactic systems are largely insensitive to the second generation population. Enhanced He in second generation stars affects also the Balmer line indices of the integrated spectra, through the change of the turn off temperature and -- in the assumption that the mass loss history of both stellar generations is the same -- the horizontal branch morphology of the underlying isochrones.
Coelho Paula
Percival Sue
Salaris Maurizio
No associations
LandOfFree
Chemical abundance anticorrelations in globular cluster stars: The effect on cluster integrated spectra does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Chemical abundance anticorrelations in globular cluster stars: The effect on cluster integrated spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemical abundance anticorrelations in globular cluster stars: The effect on cluster integrated spectra will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-355263