Astrophysics News & Events

Enter words that may appear in the title

Stellar parameters of M dwarfs: exploring the star-planet relation

N/A
Speaker
Vasco Neves (CAUP)
Event date
Venue
GAP room
Event type

Abstract: M dwarfs are the faintest, coldest and smallest stars in the main sequence. Ubiquitous and long lived, M dwarfs comprise about 70% of all stars in the Galaxy and around half of its baryonic matter. However, despite being so omnipresent and close-by, not a single M dwarf can be seen with the naked eye, due to their very low intrinsic brightness.  

 

Tidal evolution of planets around brown dwarfs

N/A
Speaker
Emeline Bolmont (U. Bordeaux 1)
Event date
Venue
GAP room
Event type
Abstract: The discovery of more than 900 planets orbiting other stars than our Sun makes this period very exciting. Our knowledge which was based on the Solar System has been challenged by new planetary systems which are very different from our system. Some of them are much more compact than the Solar System. Some planets are located extremely close-in from their star, within the orbital distance of Mercury, in a region where tidal effects are important. Understanding the structure of the known exoplanetary systems and the future ones requires to take into account the physics of tidal evolution. I will talk about the dynamical and tidal evolution of planetary systems orbiting evolving brown dwarfs. Close-in planets orbiting brown dwarfs are very interesting to study because they are influenced by tides and they can be in the habitable zone: the region around a star where a planet with an atmosphere can have water on its surface. I will show that tides are important for these systems because it has an effect on the possible habitability of planets.

Planetary dynamics and solar activity: truth and/or consequences?

Speaker
João Fernandes (Coimbra U.)
Event date
Venue
GAP room
Event type
Abstract: Since long time ago that it is been argued about a possible connection between the planets orbital motions in the solar system and the cycles of the activity of the Sun. These discussions have been based, often, on presumed correlations between the position of the planets and the occurrence of the solar maximum/minimum, but with no real physical explanation. However, very recently, Abreu et al. (2012) proposed that the planets dynamics can have an influence in the solar tachocline (a thin layer separating the solar radiative and convective regions) and, by consequence, in the activity of the Sun. Following that, several articles have been published with pro and con arguments (cf. Cameron & Schüssler 2013) . Thus, the subject is becoming particularly interesting. This talk will give a review of the current status of the discussion.

Paulo Freire's seminar on pulsars

N/A
Speaker
Paulo Freire
Event date
Venue
GAP room
Event type

The radio astronomer Paulo Freire, from the Max Planck Institute at Bonn, visited our group on September 23 and presented the latest developments on "Pulsar timing: a unique tool in Astrophysics".

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

N/A
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.

Extra-solar planets: from detection to characterization

N/A
Speaker
Nuno Santos (CAUP)
Event date
Venue
GAP room
Event type

Abstract: In this talk we will overview the major research topics of the EXOEarths team in CAUP. We will then focus our attention on a few recent results related to the detection and study of extra-solar planets. Some of the next steps in this research will also be highlighted, with a short presentation about some future facilities (ESO and ESA).

The Square Kilometer Array: radioastronomy in the XXIst century

N/A
Speaker
Domingos Barbosa (IT, Aveiro)
Event date
Venue
GAP room
Event type

Abstract: The Square Kilometer Array (SKA) will be the largest Global science project of the next two decades. It will encompass a sensor network dedicated to radioastronomy, covering two continents. SKA is a large-scale international science facility involving 67 organizations in 20 countries, as well as world industrial partners and is the only global ESFRI project.

Spin-orbit coupling for tidally evolving super-Earths

N/A
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.