We present the results of the first observations, taken with FLAMES during Science Verification, of red giant branch (RGB) stars in the globular cluster NGC 2808. A total of 137 stars was observed, of which 20 at high resolution (R=47,000) with UVES and the others at lower resolution (R=19,000-29,000) with GIRAFFE in MEDUSA mode, monitoring ∼ 3 mag down from the RGB tip. Spectra were taken of t...

The properties of 322 intermediate-mass late-G giants (comprising 10 planet-host stars) selected as the targets of Okayama Planet Search Program, many of which are red-clump giants, were comprehensively investigated by establishing their various stellar parameters (atmospheric parameters including turbulent velocity fields, metallicity, luminosity, mass, age, projected rotational velocity, etc....

We use archival Spitzer Space Telescope photometry of the old, super-solar metallicity massive open cluster NGC6791 to look for evidence of enhanced mass loss, which has been postulated to explain the optical luminosity function and low white dwarf masses in this benchmark cluster. We find a conspicuous lack of evidence for prolificacy of circumstellar dust production that would have been expec...

New HST/WFPC2 imaging of the dwarf starburst galaxy NGC625 is presented. These data, which are 80% complete to V and I magnitudes of 26.0 and 25.3 respectively, allow us to study the recent star formation history of NGC625. Using outlying red giants stars, we derive a tip of the red giant branch (TRGB) distance modulus of 27.95±0.07. This corresponds to a distance of 3.89±0.22 Mpc, placing this...

Three-dimensional stellar modeling has enabled us to identify a deep-mixing mechanism that must operate in all low mass giants. This mixing process is not optional, and is driven by a molecular weight inversion created by the He(He,2p)He reaction. In this paper we characterize the behavior of this mixing, and study its impact on the envelope abundances. It not only eliminates the problem of He ...

The results of an 18-year radial-velocity survey of 30 red giants in the field of the open cluster NGC 752 are presented. The membership of 15 stars is confirmed. Four spectroscopic binaries have been discovered among the members and three orbits have been determined for H75, 110 and 208, with periods of 3321, 127 and 5276 days respectively. The binary frequency (27%) is normal. A search for ad...

We simulate collisions involving red-giant stars in the centre of our galaxy. Such encounters may explain the observed paucity of highly luminous red giants within ∼ 0.2 pc of Sgr A⋆. The masses of the missing stars are likely to be in the range ∼ 2M⊙ − 8M⊙. Recent models of the galactic centre cluster’s density distribution and velocity dispersion are used to calculate two-body collision rates...

Our current understanding of the origin of barium and S stars is briefly reviewed, based on new orbital elements and binary frequencies. 1. The relation of barium and S stars to carbon stars Since the last conference (IAU Coll. 106, Evolution of Peculiar Red Giants, Johnson & Zuckermann eds., 1989) devoted to chemically-peculiar red giants (PRGs), much progress has been made in understanding ho...

The analyses of high resolution infrared spectra have been done for CN lines in oxygen-rich cool evolved stars including 2 K giants, 20 M giants and 1 S-type star. Since CN lines analyzed in the present work are weak and resolved well, they are appropriate for quantitative analyses. CN lines of ∆v =−2 and −1 sequences (red system) which are in the Kand the H-window regions, respectively, give t...

We present a study of a sample of LMC red giants exhibiting Long Secondary Periods (LSPs). We use radial velocities obtained from VLT spectral observations and MACHO and OGLE light curves to examine properties of the stars and to evaluate models for the cause of LSPs. This sample is much larger than the combined previous studies of Hinkle et al. (2002) and Wood, Olivier & Kawaler (2004). Binary...