Disentangling the Hercules stream

Abstract

Using high-resolution spectra of nearby F and G dwarf stars, we have investigated the detailed abundance and age structure of the Hercules stream. We find that the stars in the stream have a wide range of stellar ages, metallicities, and element abundances. By comparing to existing samples of stars in the solar neighbourhood with kinematics typical of the Galactic thin and thick disks we find that the properties of the Hercules stream distinctly separate into the abundance and age trends of the two disks. Hence, we find it unlikely that the Hercules stream is a unique Galactic stellar population, but rather a mixture of thin and thick disk stars. This points toward a dynamical origin for the Hercules stream, probably caused by the Galactic bar.

Accepted for publication in ApJ Letters

References in corpus (3)

• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• Revisiting two local constraints of the Galactic chemical evolution
• Kinematics of planet-host stars and their relation with dynamical streams in the solar neighbourhood

Cited by in corpus (7)

• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• Radial mixing and the transition between the thick and thin Galactic discs
• Re-visiting the relations: Galactic thin disc age-velocity dispersion relation
• New Constraints on the Galactic Bar
• On the age heterogeneity of the Pleiades, Hyades and Sirius moving groups
• Reconstructing fossil sub-structures of the Galactic disk: clues from abundance patterns of old open clusters and moving groups
• The Galactic Stellar Disc