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Bern University

Space Research & Planetary Sciences in Bern

Planetary population synthesis: interpreting present and future space data

Purpose and scientific content

The quest to understand planet formation has entered an explosive growth phase in the past few years, primarily thanks to the wealth of data influx provided by existing (e.g. CoRoT and KEPLER), forthcoming (e.g. GAIA) or in-project (PLATO, EUCLID) space missions. One common characteristic of these missions is that they are designed to maximize the discovery and thorough characterization of a large collection of extra solar planets. These data must therefore be treated as a statistical ensemble, whose properties must be understood.
Population synthesis is a method to take advantage of statistical properties emerging from observations, to understand underlying processes shaping a population, in our case extrasolar planets. As such, it represents a bridge between detailed - computational expensive - theoretical models and extensive observations. First generation of planetary population synthesis models have been developed over the last years in order mainly to understand ground-based observations of planets, in particular observations originationg from radial velocity measurements. Up to now, population syntheses has been successfull in demonstrating:
  • the sequential accretion process (planet formation from planetesimals, to embryos, to gas giants, and
  • migration (disc/planet angulat momentum exchange leading to change in forming planet orbital elements).
This latter aspect contitutes a paradigm shift from the concept of in-situ formation in a minimum mass nebula.
During the last years, transit space missions (CoRoT and KEPLER) have led to the discovery and first characterization of a large population of planets, revealing in particular a lot of unexpected systems, where dynamical interactions are very important, During the coming decade, the rate of discovery will grow at a very rapid pace, thanks to already flying, to-be-launched and in-project missions. Transit missions (CoROT, KEPLER PLATO) and direct imaging missions (JWST) will provide information on the unternal structure of extrasolar planets, whereas astrometric (GAIA) and possibly microlensing missions (EUCLID) will shed light on new parts of the parameter space of extrasolar planets (e.g. mass and orbital properties). Finally, both transit and astrometric survey will reveal part of the global dynamics of some planetary systems. Understanding these new observations requires not only understanding fundamental processes at work in planet formation and evolution, but also understanding the selection effectes introduced by different observational means.

The proposed team will bring together theorists and observers from different institues worldwide in order to interpret and/or predict observationnal data coming from the above-mentionned missions. For this, we will merge the efforts of the two leading groups of population synthesis worldwide, as well as expertises in astrometry, microlensing, direct imaging, planetary formation and evolution, and dynamics (planet-planet, planet-star, and disc-planet interactions). Three different types of activities will be pursued by the team: first, by working with experts in key processes involved in planet formation, we will improve the physical descritption of forming planets, protoplanetary discs, and disc/planet interactions. Second, we will compare population synthesis calculations performed by different team members, and analyze the origin of the differences. Finally, we will compare planetary population synthesis with data originating from exsting space missions, and make prediction for future ones. Our long-term objective is not only to deepen our understanding of planet formation, but also to improve the scientific return of present day and future extrasolar planet space missions.

Schedule of the meetings

  • First meeting: December, 3rd - 7th 2012
  • Second meeting: June, 23rd - 27th 2014

The team

Team member Affiliation Domain of expertise
Yann Alibert University of Bern (CH) planet formation - population synthesis - microlensing
Sean Andrew Harvard-Smithsonian Center for Astrophysics (USA) disc observation - disc modelling
Andrea Fortier University of Bern (CH) planet formation - planet/planetesimal interactions - microlensing
Andrew W. Howard UC Berkeley (USA) planet detection using Kepler - RV observations - interferometry
Shigeru Ida Tokyo Institute of Technology (Japan) planet formation - population synthesis
Masahiro Ikoma Toky Institute of Technology (Japan) planet formation - planetary structure
Willy Kley University of Tübingen (Germany) disc modelling - disk/planet interaction
Doug Lin UC Santa-Cruz (USA)
Kavli Institute (China)
planet formation - population synthesis
Rosemary Mardling Observatoire de Genève (CH)
Universit&eaigu; de Genève (CH)
Monash University (Australia)
planet/planet, disc/star, planet/star interactions
Christoph Mordasini MPIA Heidelberg (Germany) planet formation - population synthesis
Chris Ormel MPIA Heidelberg (Germany) planetesimal growth - planet/planetesimal interaction
Stephane Udry Observatoire de Genève (CH)
Universit&eaigu; de Genève (CH)
planet observation (RV, transit, astrometry) - dynamical systems