Abstract:
An abundance analysis is reported of 58-K giants identified by Famaey et al. (
2005
, A&A,
430, 165) as highly probable members of the Hercules stream selected from stars north of
the celestial equator in the
Hipparcos
catalogue. The giants have compositions spanning the
interval [Fe/H] from
−
0.17 to
+
0.42 with a mean value of
+
0.15 and relative elemental
abundances [El/Fe] representative of the Galactic thin disc. Selection effects may have biased
the selection from the
Hipparcos
catalogue against the selection of metal-poor stars. Our
reconsideration of the recent extensive survey by Bensby et al. of FG dwarfs, including metal-
poor stars, provides a [Fe/H] distribution for the Hercules stream, which is similar to that from
the 58 giants. It appears that the stream is dominated by metal-rich stars from the thin disc. We
discuss suggestions in the literature that the stream includes metal-poor stars from the thick
disc.
