16 research outputs found
Chemical analysis of eight giant stars of the globular cluster NGC 6366
The metal-rich Galactic globular cluster NGC 6366 is the fifth closest to the
Sun. Despite its interest, it has received scarce attention, and little is
known about its internal structure. Its kinematics suggests a link to the halo,
but its metallicity indicates otherwise. We present a detailed chemical
analysis of eight giant stars of NGC 6366, using high resolution and high
quality spectra (R > 40000, S/N > 60) obtained at the VLT (8.2 m) and CFHT (3.6
m) telescopes. We attempted to characterize its chemistry and to search for
evidence of multiple stellar populations. The atmospheric parameters were
derived using the method of excitation and ionization equilibrium of FeI and
FeII lines and from those atmospheric parameters we calculated the abundances
for other elements and found that none of the elements measured presents
star-to-star variation greater than the uncertainties. We compared the derived
abundances with those of other globular clusters and field stars available in
the literature. We determined a mean [Fe/H] = -0.60 +- 0.03 for NGC 6366 and
found some similarity of this object with M 71, another inner halo globular
cluster. The Na-O anticorrelation extension is short and no star-to-star
variation in Al is found. The presence of second generation stars is not
evident in NGC 6366.Comment: 17 pages, 14 figures. Accepted for publication in MNRAS; Corrected
typos and added reference