Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2010-12-09
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
Scientific paper
We present the chemical abundance analysis of 33 red giant stars belonging to the complex stellar system Terzan 5. We confirm the discovery of two stellar populations (Ferraro et al. 2009, Nature, 462,483) with distinct iron abundances: a relatively metal-poor component with [Fe/H]=-0.25 +/- 0.07 r.m.s., and another component with [Fe/H]=+0.27 +/- 0.04 r.m.s., exceeding in metallicity any known Galactic globular cluster. The two populations also show different [alpha/Fe] abundance ratios. The metal-poor component has an average [alpha/Fe]=+0.34 +/- 0.06 r.m.s., consistent with the canonical scenario for rapid enrichment by core collapse supernovae (SNe). The metal-rich component has [alpha/Fe]=+0.03 +/-i 0.04 r.m.s., suggesting that the gas from which it formed was polluted by both type II and type Ia SNe on a longer timescale. Neither of the two populations shows evidence of the [Al/Fe] over [O/Fe] anti-correlation, that is typically observed in Galactic globular clusters. Because these chemical abundance patterns are unique, we propose that Terzan 5 is not a true globular cluster, but a stellar system with a much more complex history of star formation and chemical enrichment.
Beccari Giacomo
Bellazzini Michele
Dalessandro Emanuele
Ferraro Francesco R.
Lanzoni Barbara
No associations
LandOfFree
Spectroscopy Unveils the Complex Nature of Terzan 5 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 Spectroscopy Unveils the Complex Nature of Terzan 5, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectroscopy Unveils the Complex Nature of Terzan 5 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-77366