相关论文: The Gaia-ESO Survey: Evidence of atomic diffusion …
Context. The benchmark open cluster M67 is known to have solar metallicity and similar age as the Sun. It thus provides us a great opportunity to study the properties of solar twins, as well as the evolution of Sun-like stars. Aims.…
In the era of large stellar spectroscopic surveys, there is emphasis on deriving not only stellar abundances but also ages for millions of stars. In the context of Galactic archeology, stellar ages provide a direct probe of the formation…
We present a spectroscopic study at high resolution, R~50,000, of 14 stars located on the main sequence, at the turn-off point and on the early subgiant branch in the cluster M67 in order to investigate its detailed chemical composition,…
The spatial distribution of elemental abundances in the disc of our Galaxy gives insights both on its assembly process and subsequent evolution, and on the stellar nucleogenesis of the different elements. Gradients can be traced using…
In stellar astrophysics, the study of the atmospheres of early-type stars plays a very special role. The atmospheres of these stars display a variety of different phenomena, such as the presence of large magnetic fields, strong surface…
Atomic diffusion in stars can create systematic trends of surface abundances with evolutionary stage. Globular clusters offer useful laboratories to put observational constraints on this theory as one needs to compare abundances in…
Atomic diffusion and mixing processes in stellar interiors influence the structure and the surface composition of stars. Some of these processes cannot yet be modelled from the first principles. This limits their applicability in stellar…
Open clusters are key tools to study the spatial distribution of abundances in the disk and their evolution with time. Using the first release of stellar parameters and abundances of the Gaia-ESO Survey, we analyse the chemical properties…
Detailed chemical abundance distributions for fourteen elements are derived for eight high-probability stellar members of the solar metallicity old open cluster M67 with an age of $\sim$4 Gyr. The eight stars consist of four pairs, with…
A homogeneous spectroscopic analysis of unevolved and evolved stars in the metal-poor globular cluster NGC 6397 with FLAMES-UVES reveals systematic trends of stellar surface abundances that are likely caused by atomic diffusion. This…
Stars observed in the field of an open cluster are ideal for a controlled test of chemical tagging. Using chemical tagging, one should identify the cluster members, i.e., those stars of similar chemical composition, if their composition is…
Our recent multi-band photometric study of the colour width of the lower main sequence of the open cluster M37 has revealed the presence of a sizeable initial chemical composition spread in the cluster. If initial chemical composition…
Variations in chemical abundances with evolutionary phase have been identified among stars in globular and open clusters with a wide range of metallicities. In the metal-poor clusters, these variations compare well with predictions from…
Context. Recent evidences from spectroscopic surveys point towards the presence of a metal-poor, young stellar population in the chemical thin disk. In this context, the investigation of the spatial distribution and time evolution of…
Recent Gaia photometry of the open cluster M37 have disclosed the existence of an extended main-sequence turn off -- like in Magellanic clusters younger than about 2 Gyr -- and a main sequence that is broadened in colour beyond what is…
Chemical abundances for 15 elements (C, N, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni) are presented for 83 stellar members of the 4 Gyr old solar-metallicity open cluster M67. The sample contains stars spanning a wide range of…
The chemical makeup of a star provides the fossil information of the environment where it formed. Under this premise, it should be possible to use chemical abundances to tag stars that formed within the same stellar association. This idea -…
Determining the level of chemical homogeneity in open clusters is of fundamental importance in the study of the evolution of star-forming clouds and that of the Galactic disk. Yet limiting the initial abundance spread in clusters has been…
The chemical homogeneity of surviving stellar clusters contains important clues about interstellar medium (ISM) mixing efficiency, star formation, and the enrichment history of the Galaxy. Existing measurements in a handful of open clusters…
Aims. Atomic diffusion, including the effect of radiative accelerations on individual elements, leads to important variations of the chemical composition inside the stars. The accumulation in specific layers of the elements, which are the…