Stellar formation and evolution

Star formation

Star formation is a complex and long process that occurs in the giant molecular clouds, big structures of gas, atomic and molecular, and cold dust, a few tens of K. Gravity, turbulence, magnetic field as well as feedback interactions among them, shape and organize in cascade the diffuse medium at different spatial scales. From the larger scales, comparable with those of the clouds, tens of parsec or more, where galactic processes dominate, like gravity, turbulence, Galaxy rotation, interaction with other clouds; down to smaller scales where we find the protoplanetary discs. Of the order of hundreds of astronomical units. According to the different scales, density, temperature and size change by tens of orders of magnitudes; thus, it is necessary to trace the matter with  an extensive set of observables that include photometric and spectroscopic imaging from the near-infrared to the radio, from ground and space. The Star and Planetary Formation Group at IAPS in Rome has been studying all the phases of these processes for more than 20 years, through a carefully planned and coordinated series of activities and projects that made it a group of absolute excellence in the international landscape.  The image in this page  shows the centre of our Galaxy observed with the Herschel satellite in three photometric bands at 70, 160 e 250 micron; the three images were obtained from the raw data through a code developed in collaboration with Università di Roma La Sapienza, and combined with a code developed at IAPS.

Planetary formation

The process of formation of a single star or, more frequently, of a stellar multiple system, involves also the formation of a disc. The matter in the disc, gas and dust, generates a planetary system. Our group works actively in developing theoretical models with the aim of predicting the physical and chemical evolution of such systems.

Asteroseismology

Asteroseismology indicates the study of the internal structure and dynamics of the stars from observations of their resonant vibrations. These vibrations - or oscillations - manifest themselves in small motions of the visible surface of the star and, like the seismic waves generated by earthquakes in the Earth, provide us with valuable information about the pervaded internal layers. Oscillations have several advantages over all the other observables: pulsational instability has been detected in stars in all the evolutionary stages and of different spectral type from main-sequence to the white dwarf cooling sequence; frequencies of oscillations can be measured with high accuracy and depend in very simply way on the equilibrium structure of the model; different modes propagate through different layers of the interior of a star. Thus, a sufficiently rich spectrum of observed resonant modes permit the probing of internal conditions and lead to test and revise theories of stellar structure and evolution.  Since a correct understanding of stars' evolution is a corner-stone of modern astrophysics, these endeavours are fundamentally important to the whole of astrophysics. Over the last decade, thanks to the successful photometric space missions (COROT, Kepler/K2 and TESS) mainly conceived for exoplanets, but extremely suitable for detection of stellar pulsations, Asteroseismology has produced an extraordinary revolution in astrophysics, unveiling a wealth of results on the physical properties of the stars in all the evolutionary phases.

Our group plays a major role within the international community of Asteroseismology, contributing to study the structure and evolution of the stars and their planets, the formation and dating of our galaxy and the universe’s chemical evolution.