Chemical compositions and kinematics of the Hercules stream
  An abundance analysis is reported of 58 K giants identified by Famaey et al.
(2005) 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 biassed the selection from
the Hipparcos catalogue against the selection of metal-poor stars. Our
reconsideration of the recent extensive survey of FG dwarfs which included
metal-poor stars (Bensby et al. 2014) 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. Suggestions in
the literature that the stream includes metal-poor stars from the thick disc
are discussed.
