The Hamburg/ESO R-process Enhanced Star survey (HERES)

We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe] > 1 dex; hereafter r-II stars), the Hamburg/ESO R-process Enhanced Star survey (HERES). Moderate-resolution (~2A) follow-up spectroscopy has been obtained for metal-poor giant candidates selected from the Hamburg/ESO objective-prism survey (HES) as well as the HK survey to identify sharp-lined stars with [Fe/H] < -2.5dex. For several hundred confirmed metal-poor giants brighter than B~16.5mag (most of them from the HES), ``snapshot'' spectra (R~20,000; S/N~30 per pixel) are being obtained with VLT/UVES, with the main aim of finding the 2-3% r-II stars expected to be a…

The 4MOST Survey of Dwarf Galaxies and their Stellar Streams (4DWARFS)

The present-day Milky Way is the result of a long history of mergers and interactions with smaller galaxies. The 4DWARFS survey will target the dwarf galaxies and stellar streams in the 4MOST footprint, and unveil their chrono-chemo-kinematical properties. The survey will provide radial velocities, chemical abundances and stellar ages for 140 000 stars, and thus increase the number of stars with detailed information in such systems by several orders of magnitude. 4DWARFS will provide a new, deeper view of the Milky Way environment, shedding light on the first stars, chemical evolution, dark matter halos, and hierarchical galaxy formation down to the smallest scales.

The Hamburg/ESO R-process Enhanced Star survey (HERES): Project Overview, and New r-II Stars

The Hamburg/ESO R-process Enhanced Star survey (HERES):XI. The highly r-process-enhanced star CS 29497-004

We report an abundance analysis for the highly r-process-enhanced (r-II) star CS 29497-004, a very metal-poor giant with Teff = 5013K and [Fe/H]=-2.85, whose nature was initially discovered in the course of the HERES project. Our analysis is based on high signal-to-noise, high-resolution (R~75000) VLT/UVES spectra and MARCS model atmospheres under the assumption of local thermodynamic equilibrium, and obtains abundance measurements for a total of 46 elements, 31 of which are neutron-capture elements. As is the case for the other 25 r-II stars currently known, the heavy-element abundance pattern of CS 29497-004 well-matches a scaled Solar System second peak r-process-element abundance patter…