Hot Jupiter Orbiting Closely to Its Sun

A retrograde hot Jupiter--an extrasolar planet whose mass is close to or exceeding that of Jupiter. The transiting giant planet orbits very closely to its host star and in a direction opposite the stellar rotation. This peculiar configuration results from gravitational perturbations by another, much more distant planet (seen in the upper left). Some hot Jupiters have orbits that are elongated or highly inclined, with respect to the equator of the star, and some orbit counter to the star's spin direction, but they all have very close proximity to their host star. (Date of Image: unknown) Credit: Lynette Cook