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.
THE TERZAN 5 PUZZLE: DISCOVERY OF A THIRD, METAL-POOR COMPONENT / L. Origlia;D. Massari;R. M. Rich;A. Mucciarelli;F. R. Ferraro;E. Dalessandro;B. Lanzoni. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - ELETTRONICO. - 779:(2013), pp. 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.
