Introduction This Symposium is centered on a simple idea: We have accumulated 10 years of observations of planets around MS stars. They are of a great diversity of types: Radial Velocities, Transits, and, in a yet few cases, Gravitational  Lensing, Astrometry, Spectra, Direct Imaging, Polarimetry, . The scientific community did not lost time and did already start the study of the Physics and the Dynamics of these planets. Dynamical studies started mainly after the discovery of a system of 3 planets around Upsilon Andromedae. The first stability studies were almost concomitant to the discovery paper. Then other systems came and the remarkable resonant pair around GJ 876 was discovered, raising many studies and constraining the models of planetary migration. The Physics of exoplanets is coming with a slower pace, since it depends on much  more difficult observations. But with photometric and spectroscopic observations made during transits it is possible to assess parameters as the radius of the exoplanets and have an indication on the temperature and even to get the signature of some elements in the planets atmospheres. It is already possible to consider the modelisation of the planetary atmospheres and the internal structure of the planets. In the frontier of Physics and Dynamics, the tidal, thermal  and magnetic interaction of stars and Hot Jupiters is being studied.

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Dynamics (Multi-planet systems) The number of multi-planet systems of exoplanets around MS stars is approaching 20 to date. The main concern of the dynamics of extra-solar planetary systems is the stability of the known systems and the identification of dynamical processes which may have determined their past evolution. It is expected that the systems will remain stable for times of the order of their age, but this question has to be answered for each system. Among them there are many pairs in which the orbits are relatively close one to another (the ratio of the orbital periods is small) and at least one of the components moves on a very eccentric orbit (e>0.2). These pairs are necessarily resonant (otherwise they develop instabilities in short time). The capture in resonance is an important clue on the past evolution of these systems and has conditioned the study of the interactions of these planets with the remnant of the disk from which they were formed. In the case of small eccentricities, resonance is not imposed by the stability condition and, indeed, not observed. This is the case of the outer Solar System and also, seemingly, the case of 47 UMa. We hope that by the time of the meeting, the current uncertainties on the orbit of the planets of 47 Uma will be over and that the only system twin to our Solar System be confirmed.  Additional dynamical problems arise when the system has more than one star. This is true even if only one planet is in the system if the eccentricity of the binary is large. In some yet to study cases, as 55 Cnc, we have simultaneously multiple planets and a binary star. 

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Dynamics (Hot Jupiters) Many of the known extra-solar planets are "hot Jupiters", giant planets with orbital periods of just a few days. Close-in planets are subject to strong tidal interaction with the stars. As long as just one planet is considered, the classical formulas giving the bulk variation of energy and angular momentum are enough to model the evolution of one planet. The effects on the orbital parameters of the so far discovered Hot Jupiters may tell us something about the inner structure of their host stars and of themselves. The great problem, here, is related to the unknown Love numbers and dissipation parameters (Q) of  both the star and the planet. Different theoretical predictions give values which cover four orders of magnitude. It is worthwhile adding that the inner edge of the hot Jupiters distribution is seemingly defined by a tidal limit which depends on both the semi-major axis and the planet-star mass ratio. This would arise naturally if the inner edge is related to the Roche limit, the critical distance at which a planet fills its Roche lobe. We remind that tidal  effect on close-in planets is to drive the planet to star. In at least one  case  (HD 82943), there are evidences which could support the hypothesis of the past engulfment of one planet in the star. Mass loss by evaporation shall also be taken into account in the study of the dynamical evolution of these planets. Evaporation rates due to exospheric heating by stellar XUV radiation could affect drastically the evolution and structure of planets below a critical mass. Some authors suggest that the hot-Neptunes recently discovered may originate from more massive progenitors, which have undergone strong evaporation.

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Physics (General) Extra-solar Giant Planets are often bright, massive and large tending to be  readily detected in transit surveys, and to be directly observable using  current space technology.  Spitzer allowed the recent flux detection for  HD209458b and TrEs-1. These measurements have been compared to the results obtained to the photosphere structures and spectral distribution (thermal and reflection spectra) obtained with atmosphere codes.  Uncertainties tied to the chemical composition of the atmosphere, and the presence of cloud layers are to be taken into account. The consistent treatment of the irradiated atmospheric structure and the internal, partially radiative structure have successfully reproduced observed parameters of all known transiting planets, but the case of HD 209458b still remains a mystery, with a large radius difficult to explain. HST observations have also shown an extended atmosphere of escaping hydrogen around the planet orbiting HD209458 and later also revealed the presence of Oxygen and Carbon at very high altitude in the upper atmosphere showing that the escape mechanism is a hydrodynamical blow-off of the atmosphere. Current studies show that the high temperature of the upper atmosphere (heated by the far and extreme UV stellar radiation), combined with the tidal forces, allow a very efficient evaporation of the upper atmosphere.

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Transits and CoRoT The recent have seen extraordinary increase in the number of ground-based photometric monitoring surveys. Thanks to absorption spectroscopy and secondary eclipse photometry, transiting planets are proving instrumental to a much finer understanding of the nature of hot Jupiters, giving much information inaccessible to radial velocity planet surveys: exact mass, radius, density, as well as temperature and composition. Surveys in the infrared domain may also enable us to find transiting terrestrial companions to low mass stars. To these mainly ground-based observations, we will soon add the CoRoT mission. CoRoT is a space-based transit search project that will be launched late 2006, one year before the proposed meeting. It is designed to observe up to 60000 stars during 150 days each and may contribute with the discovery of many Hot Jupiters and also terrestrial planets.

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Masses and Orbits It is well known the limitations of the radial velocity observations in what concerns the mass of the exoplanets. It is not possible to determine the inclination of the orbits over the sky plane and, as a consequence, it s not possible to extract the value of the mass from the determined M.sin I. There is the hope that, in the case of multi-planet systems with short periods, the accumulation of the mutual gravitational perturbations may be observed and be used for an independent determination of the masses. This was the case with the planets of the pulsar PSR B1257+12 and may be soon the case with the planets of GJ 876. On the other hand, some critical angles necessary to assess the stability of systems have been shown reluctant to reveal themselves (HD 82943 is an example). Transit observations also have some limitations, but it is generally possible (for the larger planets) to have also radial velocities and have a complete determination. A problem is the transit detection performance in the case of terrestrial planets as expected to be discovered with CoRoT. Our knowledge of the stars also influence the determination of the physical parameters, viz. the mass of the star in orbits determined with RV  measurements and the brightness distribution on star disks in transit data reduction.

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Planetary formation and migration. Disk-planet interaction The formation of giant planets is being studied following two different scenario. Possible formation scenarios for gas giant planets involve either  a direct gravitational instability occurring in a young protostellar disk or  the accumulation of a solid core that undergoes rapid gas accretion a critical value once the mass has reached a critical value ~ 15 Earth masses. In either case planetary formation is likely to be initiated at significantly greater distance from the star than those currently observed implying that a process of orbital migration has brought them closer to the central star. Disk-planet interaction provides a natural migration mechanism as the planet exerts torques on the protostellar disk. As a result of this, a negative torque is exerted on the planet by the outer disk and a positive torque is exerted on it by the inner disk. The result is the migration of the orbit, generally inwards, and the capture into resonance when more than one planet exist in the disk.

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Planetary Habitability The region around a star where a life-supporting biosphere can evolve is the so-called Habitable Zone (HZ). The current definition of the HZ is based on the mass-luminosity relation of the star and on climatological and meteorological considerations of Earth-like planets, From the knowledge of the planets in the Solar System, we know that planets can only evolve into a habitable world if they have a stable orbit around its host star and if they keep the atmosphere and water inventory during the period of heavy bombardment by asteroids and comets and during the host stars' active X-ray and extreme ultraviolet and stellar wind periods. Furthermore, Earth-like planets inside the HZ of low mass stars may not develop an atmosphere, because at orbital distances closer than 0.3 AU, their atmospheres are highly affected by strong stellar winds and  coronal mass ejections.

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About the city, Suzhou

The conference site, Suzhou, a city near Shanghai, is famous for its garden architecture and Chinese traditional culture. It's one of the most favorite destinations for both domestic and international tourists in China. The conference time is the best season in Suzhou.