We report on the discovery of three metal-poor giant stars in Terzan 5, a complex stellar system in the Galactic bulge, known to have two populations at [Fe/H] = -0.25 and +0.3. For these three stars we present new echelle spectra obtained with NIRSPEC at Keck II, which confirm their radial velocity membership and provide an average [Fe/H] = -0.79 dex iron abundance and [α/Fe] = +0.36 dex enhancement. This new population extends the metallicity range of Terzan 5 to 0.5 dex more metal poor, and it has properties consistent with having formed from a gas polluted by core-collapse supernovae.
L. Origlia, D. Massari, R. M. Rich, A. Mucciarelli, F. R. Ferraro, E. Dalessandro, et al. (2013). THE TERZAN 5 PUZZLE: DISCOVERY OF A THIRD, METAL-POOR COMPONENT. THE ASTROPHYSICAL JOURNAL LETTERS, 779, 5-8 [10.1088/2041-8205/779/1/L5].
THE TERZAN 5 PUZZLE: DISCOVERY OF A THIRD, METAL-POOR COMPONENT
ORIGLIA, LIVIA;MASSARI, DAVIDE;MUCCIARELLI, ALESSIO;FERRARO, FRANCESCO ROSARIO;DALESSANDRO, EMANUELE;LANZONI, BARBARA
2013
Abstract
We report on the discovery of three metal-poor giant stars in Terzan 5, a complex stellar system in the Galactic bulge, known to have two populations at [Fe/H] = -0.25 and +0.3. For these three stars we present new echelle spectra obtained with NIRSPEC at Keck II, which confirm their radial velocity membership and provide an average [Fe/H] = -0.79 dex iron abundance and [α/Fe] = +0.36 dex enhancement. This new population extends the metallicity range of Terzan 5 to 0.5 dex more metal poor, and it has properties consistent with having formed from a gas polluted by core-collapse supernovae.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
