Thursday, December 9, 2010

HR 8799 hosts jumbo planetary system

Christian Marois (Herzberg Institute of Astrophysics) and colleagues discovered a fourth giant planet orbiting HR 8799. The new planet, 'e' in the above image, lies inwards of planets b,c,d. This is typical when using imaging to hunt for extra-solar planets, since it is the closer-in planets that are harder to find, due to obscuration by the bright central star. A simulated star was actually removed from this image; the fuzzy blob seen in the center is due to imperfections in this star-subtraction process. These planets lie about 15 to 70 AU away from the central star, and have masses of ~5 to 10 Jupiter masses. So this is a jumbo planetary system, since the orbits and masses are several times larger than that the Solar System's. See the abstract of their paper in Nature for more details.