tokens: v t ) = 0.03 km s −1 and a total error on [Fe/H] of 0.03 dex. This total error takes into account all the errors on the atmospheric parameters. The two methods agree well, and we adopted σ( T eff ) = 40 K, σ(log( g )) = 0.12, σ( v t ) = 0.04, and σ([Fe/H]) = 0.03 dex as our final errors on the atmospheric parameters. Then, we choose star no. 1367 as representative of the sample, varied its T eff , log( g ), [Fe/H], and v t according to the atmospheric errors we just obtained, and redetermining the abundances. Results are shown in Table 4 , including the error due to the noise of the spectra. This error was obtained for elements whose abundance was obtained by EQWs, as the errors on the mean given by MOOG, and for elements whose abundance was obtained by spectrum-synthesis, as the error given by the fitting procedure. Δ tot is the squared sum of the single errors, while Δ tot (obs) is the error as obtained from the four repeated stars. Δ tot (obs) is equal to or smaller than Δ tot . In Table 4 , for each element, we report the observed spread of the sample (RMS obs ) with its error and in the final column the significance (in units of σ) calculated as the absolute value of the difference between RMS obs and Δ tot divided by the error on RMS obs (we choose Δ tot instead of Δ tot (obs) to be conservative). This tells us if the observed dispersion RMS obs is intrinsic or due to observational errors. Values larger than 3σ imply an intrinsic dispersion in the species chemical abundance among the cluster stars. Table 4. Estimated errors on abundances due to errors on atmospheric parameters and to spectral noise for star no. 1367 (columns 2–6). Column 7 gives the total error calculated as the root squared of the sum of the squared of columns 2–6. This total error must be compared with the total error as obtained from the 4 repeated stars (column 8) and with the observed dispersion (RMS) of the data with its error (column 9). The last column gives the significance of the difference between the total error for star no. 1367 and the observed dispersion, in units of σ. 4 RESULTS 4.1 Iron-peak, α elements and heavy elements The mean iron content we obtained is with a dispersion of Reported errors are errors on the mean. Harris ( 1996 ) gives [Fe/H] = −1.32 and we can consider the agreement satisfactory. The measured iron dispersion in Table 4 well agrees with the dispersion due to measurement errors so we have no evidence for an intrinsic Fe abundance spread. As far as iron-peak elements are concerned, Cr and Ni are solar scaled, Mn and Cu are sub-solar, and V, Co and Zn are supersolar. The α elements Si, Ca, and Ti are overabundant compared to the Sun. This is a feature common to almost all Galactic GC and halo field stars as well as to very metal-poor stars ([Fe/H] −1.5) in outer galaxies. Based on these elements, we derive for the cluster a mean α element abundance of [α/Fe] = +0.34 ± 0.01 As far as heavy elements are concerned Y, Zr, Ba, and Eu are
ner_tags: B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula B-Formula I-Formula I-Formula I-Formula I-Formula B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O B-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O B-CelestialObject I-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Software O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject I-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject I-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation O B-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O O O O O O O O B-CelestialObject O O B-CelestialObjectRegion O O O O O O O O O B-Formula I-Formula O O O O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O