Celestial Mechanics News & Events

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The structure of planetary systems: food for thought from observers to dynamicists

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Speaker
Pedro Figueira (CAUP)
Event date
Venue
GAP room
Event type
Abstract: During the last couple of years Radial Velocity and Transit surveys gathered a wealth of information about the structure of extrasolar systems. We are now putting all the information together and starting to understand the implications of these results on our understanding of the formation of planets. In this talk we will review some of the most recent results, and use the questions that are left open for dynamicists as the starting point for discussion.

Stability and Chaos in the Solar System: From Poincaré to the present

Speaker
Jacques Laskar (CNRS, Observatoire de Paris)
Event date
Venue
GAP room
Event type

Abstract: Some of the most famous works of Henri Poincaré (1854-1912) have been motivated by the problem of the stability of the Solar System. Indeed, since its formulation by Newton, this problem has fascinated astronomers and mathematicians, searching to prove the stability of the Solar System. Poincaré demonstrated that the perturbative methods of the astronomers could not be used to provide an answer to the problem of stability on infinite time because the series that were used are in general divergent. At the same time he believed that the dissipative terms would be of larger importance than the conservative neglected terms, leading to a stable final state for the Solar System. In the following of the work of Poincaré, KAM theorems have provided new hopes for mathematicians to prove the stability of the Solar System. On the opposite, the recent numerical works on realistic models of the Solar System show that the system is unstable in the strong sense and that planetary collisions are possible within the lifetime of the Sun.

Spin-orbit coupling for tidally evolving super-Earths

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Speaker
Adrian Rodriguez Colucci (Instituto de Astronomia, Geofísica e Ciências Atmosféricas, IAG-USP, Universidade de São Paulo, Brasil.)
Event date
Venue
GAP room
Event type
Abstract: We investigate the spin behavior of close-in rocky planets and the implications for their orbital evolution. The temporary captures in spin-orbit resonances are analyzed assuming that the planet rotation evolves under simultaneous actions of the torque due to the equatorial deformation and the tidal torque, both raised by the central star. We solve the spin-orbit (dissipative) problem through the simulation of the exact and averaged equations of motions. The results indicate that, whenever the planet rotation is trapped in a resonant motion, the orbital decay and the eccentricity damping are faster than the ones in which the rotation follows the so-called pseudo-synchronization. Applications are considered for the recently discovered hot super-Earths Kepler-10 b, GJ 3634 b and 55 Cnc e. The simulated dynamical history of these systems indicates the possibility of capture in several spin-orbit resonances; particularly, GJ 3634 b and 55 Cnc e can currently evolve under a non-synchronous resonant motion for suitable values of the parameters.

Welcome to Gr@v

Gr@v is a team of researchers, based at the Mathematics and Physics Department of Aveiro University, Portugal, working on strong gravity and high energy physics. The group was established in 2010. In January 2015 Gr@v integrated the FCT funded CIDMA research unit (UIDB/04106/2020 and UIDP/04106/2020), as the Gravitational Geometry and Dynamics research group. The group scientific coordinator is C. Herdeiro.