Related papers: NGC 7419 as a template for red supergiant clusters
Photometry in the B and V bands is presented for the southern stellar groups NGC 1901 and NGC 1252. NGC 1901 is often described as an open cluster while NGC 1252 consists of a concentration of about 20 stars centered approx 20' north of the…
We present the high resolution (R $\approx$ 60000), high signal-to-noise (S/N $\simeq$ 120) spectroscopic analysis of 12 red giant members of the Galactic open cluster NGC 6940. We applied Yonsei-Yale isochrones to the color-magnitude…
Two sets of archive time series observations of an old open cluster NGC 6791 were re-analysed using an image subtraction technique. We report identification of four new variables. Proper motion data are available for three of them and…
We present a binary-based reassessment of the age of the intermediate-age open cluster NGC 7789, together with well-constrained stellar parameters for twelve components in six SB2 systems, including two eclipsing binaries. Our analysis…
We present a proper motion investigation of a sample of Be star candidates towards the Magellanic Clouds, which has resulted in the identification of separate populations, in the Galactic foreground and in the Magellanic background. Be…
NGC 2420 is a $\sim$2 Gyr-old well-populated open cluster that lies about 2 kpc beyond the solar circle, in the general direction of the Galactic anti-center. Most previous abundance studies have found this cluster to be mildly metal-poor,…
We present here the first abundance analysis of 44 late B, A and F-type members of the young open cluster M6 (NGC 6405, age about 75 Myrs). Spectra, covering the 4500 to 5800 \AA{} wavelength range, were obtained using the FLAMES/GIRAFFE…
After leaving the main sequence, massive stars undergo complex evolution, still poorly understood. With a population of 100s OB stars, the starburst cluster Westerlund~1 offers an unparallelled environment to study their evolutionary…
We present B, V, R, and H alpha photometry of 8 clusters in the Small Magellanic Cloud, 5 in the Large Magellanic Cloud, and 3 Galactic clusters, and use 2 color diagrams (2-CDs) to identify candidate Be star populations in these clusters.…
We investigate the reddening and Main Sequence fitted distances to eleven young, Galactic open clusters that contain Cepheids. Each cluster contains or is associated with at least one Cepheid variable star. Reddening to the clusters is…
Deep color-magnitude diagrams are presented for poorly known open clusters Cr 261, Be 18, Be 54, Tr 5 and BH176. All clusters are old objects with age\geq 4 Gyr. BH176 is either old open cluster or young globular cluster. Extremely red…
We present new discoveries of variable stars near the turnoff of the old open cluster NGC 7142. Contrary to previous studies, we detect eight contact or near contact eclipsing binaries (including three near the cluster turnoff), and most of…
We present colour-magnitude diagrams for two rich (~10^4 Msun) Large Magellanic Cloud star clusters with ages ~10^7 years, constructed from optical and near-infrared data obtained with the Hubble Space Telescope. These data are part of an…
In a sample of six young open clusters we investigated 1753 objects using the narrow band, three filter Delta a photometric system resulting in the detection of eleven bona-fide magnetic chemically peculiar (CP) stars and five Be or…
The study of chemically peculiar (CP) stars in open clusters provides valuable information about their evolutionary status. Their detection can be performed using the $\Delta a$ photometric system, which maps a characteristic flux…
We present stellar variability towards the young open cluster NGC\,6823. Time series $V$- and $I$-band CCD photometry led to identification and characterization of 88 variable stars, of which only 14 have been previously recognized. We…
We analyse complementary HST and SUBARU data for the globular cluster NGC 2419. We make a detailed analysis of the horizontal branch (HB), that appears composed by two main groups of stars: the luminous blue HB stars ---that extend by…
An important question about Be stars is whether Be stars are born as Be stars or not. It is necessary to observe young clusters to answer this question. Observations of stars in NGC6611 and the star-formation region of Eagle Nebula have…
Context: Four open clusters are present in the Kepler field of view and timeseries of nearly a year in length are now available. These timeseries allow us to derive asteroseismic global oscillation parameters of red-giant stars in the three…
The spectral and reddening properties of 211 highly reddened proper motion members with $V < 15$ mag in 6 young galactic star clusters are investigated using low resolution spectroscopic, broad-band $UBVRIJHK$ and mid-IR data. We report…