The study of the chemical abundances of stars with different age and position in the Milky Way provide crucial information on the formation and evolution of our Galaxy. In particular, heavy elements (i.e. those with the atomic number Z > 30) are produced by the successive capture of neutrons by lighter elements. This occurs by two processes, the slow s-process
In our Galaxy, a large fraction of stars is part of binary systems. For instance, the study of Duquennoy & Mayor (1991) suggests a binary fraction of 57% for solar type stars. A slightly smaller binary fraction is expected for less massive stars. Among pre-Main Sequence stars, several binary systems are known to host a circumbinary disk. These disks are
In the Milky Way one of the main modes of star formation is in stellar clusters, which remain associated with their parental cloud for about 5-10 million years. This makes the star forming regions complex targets, characterised by rich stellar populations packed into small regions, sometime even with massive stars, and clouds whose morphology and properties are affected by the
The search of exoplanets relies mainly on two techniques: transits and radial velocity. With the former method exoplanets are revealed thanks to small and periodic dimming of the light of stars when their planets orbit across the stellar disk, producing a small eclipse. The method of radial velocity consists in revealing the oscillations of stars around the center of mass
Exploring the hot and energetic Universe Astronomers from around the world are gathering in the city of Palermo, Italy on 24-27 September to discuss the extraordinary science possible using the European Space Agency Athena mission. Due for launch at the end of the next decade, Athena will revolutionize high-energy astrophysics. Athena is an international collaboration between ESA, NASA and Japan, taking
of Mario Giuseppe Guarcello ( follow mguarce) In the past ten years the X-ray Universe has been explored mainly by two telescopes: the NASA satellite Chandra and the ESA satellite XMM-Newton. These two telescopes are still operating efficiently. However, the scientific community has already started planning the next generation of instruments for X-ray astronomy. In Europe, the future in
of Mario Giuseppe Guarcello ( follow mguarce) We are living a golden age for the research on stellar clusters and their structure, formation and evolution. This thanks to the satellite Gaia of the European Space Agency, which will provide position and radial velocity of over one billion stars with unprecedented precision, and the project Gaia-ESO Survey, an ambitious spectroscopic
of Mario Giuseppe Guarcello ( follow mguarce) We know that the intensity of the magnetic activity in the Sun (e.g.: the family of magnetic phenomena including spots, faculae, flares, etc…) varies with an 11-years cycle. Do all the stars have such a magnetic cycle? If yes, how does it change with stellar properties (mainly mass, rotation and evolutionary phase)?
di Mario Giuseppe Guarcello ( follow mguarce) Type Ia supernovae are particularly important in cosmology since they allow us precise measurements of the hosting galaxies. These supernovae are not triggered by the collapse of the core of massive stars, such as the “core-collapse supernovae”. They are instead due to the thermonuclear explosion of a white dwarf in close binary
OB associations are groups of massive stars (with spectral type O and B, more massive than 3.5 solar masses) which typically cover wide regions in the sky. The presence of such a rich population of massive stars suggests the presence of even a larger population of low-mass stars. There exists, in fact, a relation between the number of stars in
