Title: Formation of massive planets in binary star systems Authors: Willy Kley (1), ((1) University of Tuebingen)
As of today over 40 planetary systems have been discovered in binary star systems. In all cases the configuration appears to be circumstellar, where the planets orbit around one of the stars, the secondary acting as a perturber. The formation of planets in binary star systems is more difficult than around single stars due to the gravitational action of the companion on the dynamics of the protoplanetary disk. In this contribution we first briefly present the relevant observational evidence for planets in binary systems. Then the dynamical influence that a secondary companion has on a circumstellar disk will be analysed through fully hydrodynamical simulations. We demonstrate that the disk becomes eccentric and shows a coherent precession around the primary star. Finally, fully hydrodynamical simulations of evolving protoplanets embedded in disks in binary star systems are presented. We investigate how the orbital evolution of protoplanetary embryos and their mass growth from cores to massive planets might be affected in this very dynamical environment. We consider, in particular, the planet orbiting the primary in the system Gamma Cephei.
Title: Naming the extrasolar planets Authors: W. Lyra (Version v2)
Extrasolar planets are not named and are referred to only by their assigned scientific designation. The reason given by the IAU to not name the planets is that it is considered impractical as planets are expected to be common. I advance some reasons as to why this logic is flawed, and suggest names for the 403 extrasolar planet candidates known as of Oct 2009, based on the continued tradition of names from Roman-Greek mythology.
This newly discovered exoplanet orbits the star Gliese 667 C, which belongs to a triple system. The six Earth-mass exoplanet circulates around its low-mass host star at a distance equal to only 1/20th of the Earth-Sun distance. The host star is a companion to two other low-mass stars, which are seen here in the distance.
Astronomers announced today the discovery of 32 extrasolar planets, some just five times the mass of Earth and others five times heftier than giant Jupiter.
Next month may see a Nobel Prize for the discovery of the first planet outside our solar system. Canadians won that race, but may have hesitated too long to share in the credit Source
The Hot Saturn Exoplanet Of the roughly 350 known exoplanets (i.e., extrasolar planets), the one orbiting the star HD149026 is unique. It has a mass comparable to that of Saturn but is much smaller in size, indicating that it is made up of a denser material such as ice or rocks. It is therefore quite unlike the large class of "hot Jupiters," giant exoplanets that are primarily composed of hydrogen and helium (and that are hot because they orbit close to their parent stars). The comparatively unusual composition of this exoplanet may reflect the chemistry of the original stellar nebula, or perhaps something in the way it formed, or a combination of factors. Whatever the reasons, astronomers suspect that the atmosphere of this planet could also be comparatively unusual. As scientists explore the incredible, new field of exoplanet astronomy, these and other basic questions help to illuminate how our own earth was formed and how it is influenced by the sun.
In the constellation of cancer, astronomer Debra Fisher and her students discovered that a star called 55 Cancri has something no other star outside of our solar system has -- five planets orbiting it. That's a record!
"Just finding a system that is so full of planets tells us that planet formation is easy" - Debra Fischer
The nearest Earth out there in space? It might be next door, galactically speaking. Competing teams of astronomers from the United States and Europe are in a race to find a planet in orbit around our neighbours Alpha Centauri A and Alpha Centauri B, twin stars that appear to us as a single point of light. Source
Astronomers have found what appears to be a gigantic suicidal planet. The odd, fiery planet is so close to its star and so large that it is triggering tremendous plasma tides on the star. Those powerful tides are in turn warping the planet's zippy less-than-a-day orbit around its star. The result: an ever-closer tango of death, with the planet eventually spiralling into the star.