Related papers: Rotation and activity in the solar-metallicity ope…
Within the context of a large project aimed at studying early F-, A- and late B-type stars we present the abundance analysis of the photospheres of 21 members of the open cluster NGC 5460, an intermediate age cluster (logt ~ 8.2) previously…
We wish to measure the cool star rotation period distribution for the Pleiades-age rich open cluster NGC 2516 and use it to determine whether cluster-to-cluster variations exist in otherwise identical open clusters. We obtained 42 d-long…
We present the results of a 0.86 square degree CCD photometric survey of the open cluster NGC 2516, which has an age of about 150 Myr and may have a much lower metallicity than the similarly-aged Pleiades. We select a preliminary catalogue…
We derive astrophysical parameters of the open cluster NGC 1513 by means of colour indices built with new $CCD\,UBV(RI)_{KC}$ photometry. Based on early-type members, the mean foreground reddening and total to selective extinction ratio are…
Using a novel technique, which combines previously determined rotation periods with new spectroscopic determinations of projected rotation velocity, we have determined radii for fast rotating, low-mass (0.2-0.7 Msun) M-dwarfs in the young,…
Lithium (Li) abundance is an age indicator for G, K, and M stellar types, as its abundance decreases over time for these spectral types. However, despite the observational efforts made over the past few decades, the role of rotation,…
We report radial velocities (RVs), projected equatorial velocities (v sin i) and CaII triplet (CaT) chromospheric activity indices for 237 late-K to mid-M candidate members of the young open cluster NGC 2516. These stars have rotation…
We report on the results of an i-band time-series photometric survey of NGC 2516 using the CTIO 4m Blanco telescope and 8k Mosaic-II detector, achieving better than 1% photometric precision per data point over 15<~i<~19. Candidate cluster…
We further study the unusual trend we found at statistically significant levels in some globular clusters, including NGC 3201: a decreasing iron abundance in red giants towards the cluster centers. We first show that recently published new…
We have compiled two new Galactic open cluster catalogues. The first one has 119 objects with age, distance and metallicity data, while the second one has 144 objects with both absolute proper motion and radial velocity data, of which 45…
We present new (V,V-I)-photometry of the metal-rich globular clusters NGC 5927, 6316, 6342, 6441 and 6760. The clusters show differential reddening up to dE(V-I)=0.32 mag, for which the CMDs are corrected via extinction maps. There are…
High-resolution optical spectra of eighteen blue horizontal-branch (BHB) stars in the globular cluster M15 indicate that their stellar rotation rates and photospheric compositions vary strongly as a function of effective temperature. Among…
We report on a new, wide field ($20^{\prime} \times 20^{\prime}$), multicolor ($UBVI$), photometric campaign in the area of the nearby old open cluster NGC 2112. At the same time, we provide medium-resolution spectroscopy of 35 (and…
We have carried out spectrophotometry in the range 3600--9700\AA~ of five globular clusters in NGC 5128 for which previous photometric studies suggested a high metal content. We compare the equivalent widths of a set of metallic features of…
High-dispersion spectra of 333 stars in the open cluster NGC 6819, obtained using the HYDRA spectrograph on the WIYN 3.5m telescope, have been analyzed to determine the abundances of iron and other metals from lines in the 400 A region…
We present a moderate-resolution spectroscopic analysis of the 10-25 Myr clusters NGC 7160 and NGC 2232, using observations obtained with the WIYN 3.5-m telescope. Both NGC 7160 and NGC 2232 are found to have super-solar metallicities, with…
We present the $UBVRI$ CCD photometry in the region of the open cluster NGC 2421. Radius of the cluster is determined as $\sim$ 3$^\prime$.0 using stellar density profile. Our Study indicates that metallicity of the cluster is $Z \sim$…
The coronal soft X-ray emission of cool stars, especially when taken in combination with their measured rotation periods, offers insights into their levels of magnetic activity and related transitions. We study the X-ray properties of…
We present results of spectroscopic observations of selected stars in the southern open cluster NGC 6134. We have determined the rotational velocities of the six known Delta Scuti Stars in NGC 6134 as well as several other non-variable…
We present radial velocity measurements for 74 globular clusters (GCs) in the nearby giant elliptical NGC 5128, of which 31 are newly discovered clusters. All the GC candidates were taken from the list of possible new clusters given in the…