Ricerc@Sapienza

Twenty-three years ago astronomers announced the discovery of 51 Pegasi-b, the first confirmed planet orbiting a Sun-like star. The tally of known extrasolar planets now stands at 3793 planets, 2837 planetary systems (http://exoplanet.eu/) with nearly 2423 more candidates waiting to be confirmed.
In this general framework, the present project will deal with 2 new, peculiar topics of exoplanet physics, shown to be of great interest by the rapidly growing observational evidence. One refers to the dynamical features of multiplanet extrasolar systems (i.e. several planets orbiting a star), the second to planets orbiting a binary or even multiple star system, both in isolation and in a stellar environment (a star cluster). With this project, we intend to investigate the dynamical properties of such systems both by analytical and numerical methods.
A few questions to answer are:

- is it a mere coincidence that the maximum number of planets observed so far around a single star is 7-8 ?
- is this limited number due to effects of the environment?
- has the external and internal (hosting star) tidal field played a role in the number and location of planets?
- if the answer to the previous question is positive, is this tidal field responsible also for placing planets of the famous TRAPPIST-1 system in orbital resonance?
- are circumbinary disks stable?
- how is it possible to form planet around a binary star?

We aim to answer these questions in the frame of the GAPS (Global Architecture of Planetary Systems), collaboration (http://www.oact.inaf.it/exoit/EXO-IT/Projects/Entries/2011/12/27_GAPS.html) and in collaboration with the foreign institutions indicated below.
Our specific task is the investigation of the evolution of orbits of protoplanets still in their birth discs and of multiple planets around a single and binary star.
These systems will be studied in isolation as well as in a more or less dense environment (an "open" or "globular" star cluster).