Interiors of extrasolar planets: A first stepA team of European astronomers, led by T. Guillot (CNRS, Observatoire de la Côte d'Azur, France), will publish a new study of the physics of Pegasids (also known as hot Jupiters) in Astronomy & Astrophysics. They found that the amount of heavy elements in Pegasids is correlated to the metallicity of their parent stars. This is a first step in understanding the physical nature of the extrasolar planets.
Astronomy & Astrophysics
Tuesday, May 30, 2006
Up to now, astronomers have discovered 188 extrasolar planets, among which 10 are known as "transiting planets". These planets pass between their star and us at each orbit (Figure 1). Given the current technical limitations, the only transiting planets that can be detected are giant planets orbiting close to their parent star known as "hot Jupiters" or Pegasids. The ten transiting planets known thus far have masses between 110 and 430 Earth masses (for comparison, Jupiter, with 318 Earth masses, is the most massive planet in our Solar System).
Fig. 1 - Animation of a typical Pegasid system, with both the star and planet drawn to scale. Here, the planet orbits the star in just 3.5 days. For comparison, the Earth orbits the Sun every single year, and Mercury, which has the shortest orbital period in the solar system, orbits the Sun every 88 days.
