Kepler-56b (KOI-1241.02)[2] is a hot Neptune[1]—a class of exoplanets—located roughly 3,060 light-years (940 parsecs) away. It is somewhat larger than Neptune[3] and orbits its parent star Kepler-56 and was discovered in 2013 by the Kepler Space Telescope.

Kepler-56b

A diagram of the planetary system of Kepler-56
Discovery
Discovered by	Daniel Huber et al.[1]
Discovery date	16 October 2013
Detection method	Transit method
Orbital characteristics
Semi-major axis	0.1028 ± 0.0037 AU (15,380,000 ± 550,000 km)[1]
Orbital period (sidereal)	10.5016+0.0011 −0.0010[1] d
Star	Kepler-56
Physical characteristics
Mean radius	6.51+0.29 −0.28[1] REarth
Mass	22.1+3.9 −3.6[1] MEarth
Mean density	0.442+0.080 −0.072 g cm−3

Planetary orbit

Kepler-56b is about 0.1028 AU (9.56 million mi; 15.38 million km) away from its host star[1] (about one-tenth of the distance between Earth to the Sun), making it even closer to its parent star than Mercury (0.387098 AU (35.9830 million mi; 57.9090 million km)) and Venus (0.723332 AU (67.2379 million mi; 108.209 million km)). It takes 10.5 days for Kepler-56b to complete a full orbit around Kepler-56.[1] Further research shows that Kepler-56b's orbit is about 45° misaligned to the host star's equator. Later radial velocity measurements have revealed evidence of a gravitational perturbation but currently it is not clear if it is a nearby star or a third planet (a possible Kepler-56d).

Both Kepler-56b and Kepler-56c will be devoured by their parent star in about 130 and 155 million years.[4] 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.[4] The measured mass of Kepler-56b is about 30% larger than Neptune's mass, but its radius is roughly 70% larger than Neptune's. Therefore, Kepler-56b should have a hydrogen/helium envelope containing a significant fraction of its total mass.[5][6] 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.[7] Nonetheless, the planet may have been significantly more massive in the past and may keep losing mass in the future.

References

Further reading

• Steffen, Jason H; Fabrycky, Daniel C; Agol, Eric; et al. (20 August 2012). "Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability". Mon. Not. R. Astron. Soc. 428 (2): 1077. arXiv:1208.3499. Bibcode:2013MNRAS.428.1077S. doi:10.1093/mnras/sts090.

External links

• "Kepler-56b". kepler.nasa.gov. Archived from the original on 2015-09-26. Retrieved 2016-01-02.
• Megan Smith (8 June 2014). "Star to Swallow not One, but Two Exoplanets". Futurism LLC.

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