Kepler-56b
A diagram of the planetary system of Kepler-56
Discovery
Discovered byDaniel Huber et al.[1]
Discovery date16 October 2013
Transit method
Orbital characteristics
0.1028 ± 0.0037 AU (15,380,000 ± 550,000 km)[1]
10.5016+0.0011
−0.0010[1] d
StarKepler-56
Physical characteristics
Mean radius
6.51+0.29
−0.28[1] R🜨
Mass22.1+3.9
−3.6[1] MEarth
Mean density
0.442+0.080
−0.072 g cm−3

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.

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 (0.39 AU [36 million mi; 58 million km]) and Venus (0.72 AU [67 million mi; 110 million km]). It takes 10.5 days for Kepler-56b to complete a full orbit around its star.[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 from 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.

Other planets in the Kepler-56 system

References

  1. ^ a b c d e f g h Huber, D.; et al. (2013). "Stellar Spin-Orbit Misalignment in a Multiplanet System". Science. 342 (6156): 331–334. arXiv:1310.4503. Bibcode:2013Sci...342..331H. doi:10.1126/science.1242066. PMID 24136961. S2CID 1056370.
  2. ^ "KOI-1241.02". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-07.
  3. ^ "NASA Exoplanet Archive". NASA Exoplanet Archive. Operated by the California Institute of Technology, under contract with NASA.
  4. ^ a b Charles Poladian (2014-06-03). "Cosmic Snack: Planets Kepler-56b And Kepler-56c Will Be Swallowed Whole By Host Star". International Business Times. Retrieved 2017-09-07.
  5. ^ Lissauer, J. J.; Hubickyj, O.; D'Angelo, G.; Bodenheimer, P. (2009). "Models of Jupiter's growth incorporating thermal and hydrodynamic constraints". Icarus. 199 (2): 338–350. arXiv:0810.5186. Bibcode:2009Icar..199..338L. doi:10.1016/j.icarus.2008.10.004. S2CID 18964068.
  6. ^ D'Angelo, G.; Weidenschilling, S. J.; Lissauer, J. J.; Bodenheimer, P. (2014). "Growth of Jupiter: Enhancement of core accretion by a voluminous low-mass envelope". Icarus. 241: 298–312. arXiv:1405.7305. Bibcode:2014Icar..241..298D. doi:10.1016/j.icarus.2014.06.029. S2CID 118572605.
  7. ^ a b D'Angelo, G.; Bodenheimer, P. (2016). "In Situ and Ex Situ Formation Models of Kepler 11 Planets". The Astrophysical Journal. 828 (1): id. 33. arXiv:1606.08088. Bibcode:2016ApJ...828...33D. doi:10.3847/0004-637X/828/1/33. S2CID 119203398.

Further reading

External links


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