Kepler-56b is an extrasolar planet orbiting the red giant star Kepler-56. It is approximately 3,060 light years away from Earth, in the constellation of Cygnus.
Characteristics and orbit[]
The planet is somewhat larger than Neptune and orbits its host star at a distance of around 0.1028 AU, several times closer than Mercury orbits the Sun. It takes around 10.5 Earth days for Kepler-56b to complete an orbit around its star. Kepler-56b's orbit is about 45° misaligned to the host star's equator. Radial velocity measurements have revealed evidence of a gravitational perturbation but it is not clear whether this is a nearby star or a third planet.
In approximately 130-155 million years, both Kepler-56b and Kepler-56c will be devoured byits host star. Even further research shows that it will have its atmosphere boiled away by intense heat from the star, and it will be stretched by the strengthening stellar tides. The measured mass of Kepler-56b is around 30% larger than Neptune's mass, although its radius is around 70% larger than Neptune's. Therefor, Kepler-56b should have a hydrogen/helium envelopoe containing a significant fraction of its total mass. Like Kepler-11b and Kepler-11c, the envelope's light elements are susceptible to photo-evaporation caused by radiation from the central star. For example, it has been calculated that Kepler-11c lost over 50% of its hydrogen/helium envelope after formation.[7] However, the larger mass of Kepler-56b, compared to that of Kepler-11c, reduces the efficiency of mass loss. Nonetheless, the planet may have been significantly more massive in the past and may keep losing mass in the future.