Related papers: Membership and lithium in the old, metal-poor open…
We conducted an analysis of the distribution of elements from lithium to europium in 200 dwarfs in the solar neighbourhood ~20 pc with temperatures in the range 4800-6200 K and metallicities [Fe/H] higher than -0.5 dex. Determinations of…
A sample of metal-poor subgiants has been observed with the UVES spectrograph at the Very Large Telescope and abundances of Li and Be have been determined. Typical signal-to-noise per spectral bin values for the co-added spectra are of the…
We report the discovery of a lithium dip (Li-dip) in the stellar "Snake" (age = $35 \pm 5$ Myr), challenging the classical view that Li-dips emerge only at ages $\gtrsim 150$ Myr. Using high-resolution spectra from GALAH DR4 ($R \sim…
An extensive beryllium abundance analysis was conducted for 118 solar analogs (along with 87 FGK standard stars) by applying the spectrum synthesis technique to the near-UV region comprising the Be II line at 3131.066 A, in an attempt to…
The lithium present in the photospheres of solar-type stars is transported to the inner parts by convection, reaching regions even somewhat below the convection zone, by non-standard transport mechanisms. In stars with deeper convective…
We present FLAMES/GIRAFFE spectroscopy obtained at the Very Large Telescope (VLT). Using these observations we have been able for the first time to observe the Li I doublet in the Main Sequence stars of a Globular Cluster. We also observed…
We report on near IR ($J$ and $K$ bands) observations of two $8 \times 8 \~(arcmin)^{2}$ regions centered on the old open clusters Berkeley~17 and Berkeley~18, for which only optical photometry (in $B$,$V$ and $I$ bands) exists. $J$ and $K$…
We present a decade-long investigation of a poorly studied cluster, Berkeley 65 (Be 65), using deep optical data from the telescopes of ARIES, Nainital Observatory. We estimate its radius ($R_{cluster}$ = 1.6$^{'}$, aspect ratio of…
We present radial velocities and chemical abundances for nine stars in the old, distant open clusters Be 18, Be 21, Be 22, Be 32, and PWM 4. For Be 18 and PWM 4, these are the first chemical abundance measurements. Combining our data with…
We present precision radial velocities and stellar population parameters for 77 star clusters in the Local Group galaxy M33. Our GTC and WHT observations sample both young, massive clusters and known/candidate globular clusters, spanning…
To study the crucial range of Galactocentric distances between 12 and 16 kpc, where little information is available, we have obtained VI CCD imaging of Berkeley 20 and BVI CCD imaging of Berkeley 66 and Tombaugh 2, three distant, old open…
The Li abundances of the two components of the very metal-poor ([Fe/H]=-2.5) double-lined spectroscopic binary G166-45 (BD+26 2606) are determined separately based on high resolution spectra obtained with the Subaru Telescope High…
We obtain lithium abundances for G and K stars in Blanco 1, an open cluster with an age similar to, or slightly younger than, the Pleiades. We critically examine previous spectroscopic abundance analyses of Blanco 1 and conclude that while…
The light element lithium is formed by nucleosynthesis during the Big Bang. Its abundance can help to define the parameters of the early universe. To find this primordial value, it is necessary to determine Li abundances in the oldest stars…
A comprehensive census of Galactic open cluster properties places unique constraints on the Galactic disc structure and evolution. In this framework we investigate the evolutionary status of three poorly-studied open clusters, Berkeley 31,…
Lithium is predicted, and observed, to be depleted in contracting, low-mass pre main sequence (PMS) stars. Yet these stars reach the zero age main sequence (ZAMS) with a spread in lithium abundance at a given effective temperature that is…
Galactic open clusters have been long recognized as one of the best tools to investigate the chemical content of Galactic disk and its time evolution. In the last decade, many efforts have been directed to chemically characterize the old…
Context: Open clusters are ideal laboratories to investigate a variety of astrophysical topics, from the properties of the Galactic disc to stellar evolution models. For this purpose, we need to know their chemical composition in detail.…
We present new ages and abundance measurements for the pre-main sequence star PZ Tel. PZ Tel was recently found to host a young and low-mass companion. Using FEROS spectra we have measured atomic abundances (e.g. Fe and Li) and…
HYDRA spectra of 287 stars in the field of NGC 2506 from the turnoff through the giant branch are analyzed. With previous data, 22 are identified as probable binaries; 90 more are classified as potential non-members. Spectroscopic analyses…