Related papers: C3PO V: Comoving stellar pairs indicate rotational…

Open clusters (OC) of 1-3 Gyr age contain intermediate-to-low-mass stars in evolutionary phases of multiple relevance to understanding Li evolution. Stars leaving the main sequence (MS) from the hot side of the Lithium dip (LD) at a fixed…

More than 600 high resolution spectra of stars with spectral type F and later were obtained in order to search for signatures of differential rotation in line profiles. In 147 stars, the rotation law could be measured, 28 of them are found…

We present lithium abundances for ~50 X-ray selected candidate members of the 30-50 Myr old open clusters IC 2602 and IC 2391. These data enlarge and extend to cooler temperatures previous Li surveys of these clusters by Stauffer et al.…

The lithium abundance, A(Li), in stellar atmospheres suffers from various enhancement and depletion processes during the star's lifetime. While several studies have demonstrated that these processes are linked to the physics of stellar…

Early-type stars have convective cores due to a steep temperature gradient produced by the CNO cycle. These cores can host dynamos, and the generated magnetic fields can be relevant to explain the magnetism observed in Ap/Bp stars. Our main…

We present a first set of results concerning stellar evolution of rotating low-mass stars. Our models include fully consistent transport of angular momentum and chemicals due to the combined action of rotation induced mixing (according to…

The spin-down of Be stars due to angular momentum transport from star to disc has been considered. This has been prompted by empirical studies of observed optical and IR line profile studies indicating that the disc is rotating in a…

Lithium abundances in a selected sample of halo stars have been revised by using the new accurate IRFM effective temperatures by Alonso, Arribas & Martinez-Roger (1996a). From 41 plateau stars (Teff > 5700 and [Fe/H] <= -1.5) we found no…

Fully convective M dwarfs typically remain rapidly rotating and magnetically active for billions of years, followed by an abrupt and mass-dependent transition to slow rotation and quiescence. A robust understanding of this process is…

Stellar rotation significantly shapes the evolution of massive stars, yet the interplay of mass and metallicity remains elusive, limiting our capacity to construct accurate stellar evolution models and to better estimate the impact of…

Tidal interactions are one of the primary drivers of orbital evolution for massive planets with short orbital periods. Tidal dissipation within host stars can cause the orbits of such planets to decay. However, the mechanisms of tidal…

Precision UBVRI photometry of NGC 7789 is combined with Gaia data to map reddening variations across the cluster face. HYDRA spectra, Gaia astrometry, and isochrone fitting constrain the absolute reddening, apparent modulus, and age to…

Solar-type stars form with a wide range of rotation rates. A wide range persists until a stellar age of 0.6 Gyr, after which solar-type stars exhibit Skumanich spin-down. Rotational evolution models incorporating polytropic stellar winds…

We combine stellar surface rotation periods determined from NASA's Kepler mission with spectroscopic temperatures to demonstrate the existence of pileups at the long-period and short-period edges of the temperature-period distribution for…

We revisit large spectroscopic data sets for field stars from the literature to derive the upper Li envelope in the high metallicity regime in our Galaxy. We take advantage of Gaia EDR3 data and state-of-the-art stellar models to precisely…

During most of their life, stars fuse hydrogen into helium in their cores. The mixing of chemical elements in the radiative envelope of stars with a convective core is able to replenish the core with extra fuel. If effective, such deep…

Context. The rotation period of stars is an important parameter along with mass, radius, effective temperature. It is an essential parameter for any radial velocity monitoring, as stellar activity can mimic the presence of a planet at the…

High Li abundances have been reported in the late type secondaries of five soft X-ray transients (SXTs), V404 Cyg, A0620-00, GS2000+25, Nova Mus 1991, and Cen X-4. Since Li is likely to be depleted in stars of this type, the origin of the…

Within the scope of a Key Programme determining fundamental parameters of stars observed by HIPPARCOS, spectra of 525 B8 to F2-type stars brighter than V=8 have been collected at ESO. Fourier transforms of several line profiles in the range…

I summarize the results of 15 years of research on the surface abundances of stars in globular clusters. Globular-cluster stars afford a unique view of the physical processes that shape the surface abundances of stars on and beyond the…