Related papers: The Age and Stellar Parameters of the Procyon Bina…
We show how the recent discovery of a likely close white dwarf companion to the well known star Regulus, one of the brightest stars in the sky, leads to considerable insight into the prior evolutionary history of this star, including the…
We present the results of the high-resolution spectroscopic observations of the neglected binary system HD\,194495 (B3\,IV-V+B4\,V). A combined analysis of three different photometric data set ($Tycho$ B$_T$ and V$_T$ photometry, H$_p$-band…
Using high-precision observations from the space-based \textit{Gaia} and \textit{TESS} missions, complemented by ground-based spectroscopic data and multi-band photometric surveys, we perform a detailed investigation of the Galactic open…
We explore the probable chemical signature of planet formation in the remarkable binary system HD 106515. The A star hosts a massive long-period planet with 9 MJup detected by radial velocity. We also refine stellar and planetary parameters…
We report the discovery, from our preliminary survey of the Praesepe open cluster, of two new spectroscopically confirmed white dwarf candidate members. We derive the effective temperatures and surface gravities of WD0837+218 and WD0837+185…
We have carried out a multi-site campaign to measure oscillations in the F5 star Procyon A. We obtained high-precision velocity observations over more than three weeks with eleven telescopes, with almost continuous coverage for the central…
We observe the brightest member of the Praesepe cluster, Epsilon Cancri, to precisely measure the characteristics of the stars in this binary system, en route to a new measurement of the cluster's age. We present spectroscopic radial…
We present new V-band differential photometry and radial-velocity measurements of the unevolved 1.18-day period F+G-type double-lined eclipsing binary VZ Cep. We determine accurate values for the absolute masses, radii, and effective…
The unprecedented quality of the asteroseismic data of solar-type stars made available by space missions such as NASA's Kepler telescope are making it possible to explore stellar interior structures. This offers possibilities of…
A previous study of correlations between element abundance ratios, [X/Fe], and ages of solar twin stars is extended to include Sc, Mn, Cu, and Ba. HARPS spectra with S/N > 600 are used to derive very precise (+/- 0.01 dex) differential…
We report the spectroscopic confirmation of four further white dwarf members of Praesepe. This brings the total number of confirmed white dwarf members to eleven making this the second largest collection of these objects in an open cluster…
VHS J1256$-$1257 AB is an ultracool dwarf binary that hosts a wide-separation planetary-mass companion that is a key target of the {\sl JWST} Exoplanet Early Release Science (ERS) program. Using Keck adaptive optics imaging and aperture…
Castor is a system of six stars in which the two brighter objects, Castor A and B, revolve around each other every $\sim$450 yr and are both short-period spectroscopic binaries. They are attended by the more distant Castor C, which is also…
We have exploited Gaia Data Release 2 to study white dwarf members of the Praesepe star cluster. We recovered eleven known white dwarf members (all DA spectral type) plus a new cluster WD never identified before. Two of the eleven known DA…
We present Hubble Space Telescope UV spectra of the 4.6 h period double white dwarf SDSS J125733.63+542850.5. Combined with Sloan Digital Sky Survey optical data, these reveal that the massive white dwarf (secondary) has an effective…
AR Aur A+B is a close binary of astrophysical interest, because dissimilar surface compositions are reported between similar late B-type dwarfs. A new spectroscopic study on this system was carried out based on the disentangled spectra, in…
HIP 45734 is a quadruple system of 2+2 architecture located at 68 pc from the Sun. The outer 9" system A,B has a period of ~10^4 yr. The pair Aa,Ab is a visual binary with a period of 20.1 years and an eccentricity of 0.78. Its periastron…
The visually close binary system HD25811 is analyzed to estimate its physical and geometrical parameters in addition to its spectral type and luminosity class. The method depends on obtaining the best fit between the entire observational…
We construct a set of binary evolutionary sequences for systems composed by a normal, solar composition, donor star together with a neutron star. We consider a variety of masses for each star as well as for the initial orbital period…
Binary stars in which oscillations can be studied in either or both components can provide powerful constraints on our understanding of stellar physics. The bright binary 12 Bo\"otis (12 Boo) is a particularly promising system because the…