Kepler-56b
{{Short description|Hot Neptune orbiting Kepler-56}}
{{Infobox planet
| name = Kepler-56b
| image = Kepler-56 System Diagram.jpg
| caption = A diagram of the planetary system of Kepler-56
| discoverer = Daniel Huber et al.
| discovered = 16 October 2013
| discovery_method = Transit method
| apsis = astron
| period = {{val|10.5016|+0.0011|-0.0010}} d
| star = Kepler-56
| mean_radius = {{val|6.51|+0.29|-0.28}} {{Earth radius|link=y}}
| mass = {{val|22.1|+3.9|-3.6}} {{Earth mass|sym=y|link=y}}
| density = {{val|0.442|+0.080|-0.072}} g cm−3
}}
Kepler-56b (KOI-1241.02) is a hot Neptune—a class of exoplanets—located roughly {{Convert|3060|ly|pc|lk=on|abbr=off}} away. It is somewhat larger than Neptune{{cite web|title=NASA Exoplanet Archive|url=https://exoplanetarchive.ipac.caltech.edu/index.html|website=NASA Exoplanet Archive|publisher=Operated by the California Institute of Technology, under contract with NASA}} and orbits its parent star Kepler-56 and was discovered in 2013 by the Kepler Space Telescope.
Planetary orbit
Kepler-56b is about {{Convert|0.1028|AU|e6mi e6km|lk=on|abbr=unit}} away from its host star (about one-tenth of the distance between Earth to the Sun), making it even closer to its parent star than Mercury ({{convert|0.39|AU|e6mi e6km|sigfig=2|abbr=unit|disp=sqbr}}) and Venus ({{convert|0.72|AU|e6mi e6km|sigfig=2|abbr=unit|disp=sqbr}}). It takes 10.5 days for Kepler-56b to complete a full orbit around its star. 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. 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 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.{{cite journal|last1=Lissauer|first1=J. J.|last2=Hubickyj|first2=O. |last3=D'Angelo|first3=G. |last4=Bodenheimer|first4=P. |title=Models of Jupiter's growth incorporating thermal and hydrodynamic constraints| journal=Icarus|year=2009|volume=199|issue=2| pages=338–350|arxiv=0810.5186|doi=10.1016/j.icarus.2008.10.004|bibcode=2009Icar..199..338L|s2cid=18964068 }}{{cite journal|last=D'Angelo|first=G.|author2=Weidenschilling, S. J. |author3=Lissauer, J. J. |author4=Bodenheimer, P. |title=Growth of Jupiter: Enhancement of core accretion by a voluminous low-mass envelope|journal=Icarus|date=2014|volume=241|pages=298–312|arxiv=1405.7305|doi=10.1016/j.icarus.2014.06.029|bibcode=2014Icar..241..298D|s2cid=118572605 }} 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.{{cite journal|last=D'Angelo|first=G.|author2= Bodenheimer, P. |title=In Situ and Ex Situ Formation Models of Kepler 11 Planets|journal=The Astrophysical Journal|year=2016|volume=828|issue=1|pages=id. 33|doi=10.3847/0004-637X/828/1/33|arxiv = 1606.08088 |bibcode = 2016ApJ...828...33D |s2cid=119203398 |doi-access=free }} 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.
Other planets in the Kepler-56 system
References
{{reflist|refs=
{{cite news |url= http://www.ibtimes.com/cosmic-snack-planets-kepler-56b-kepler-56c-will-be-swallowed-whole-host-star-1593918 |title= Cosmic Snack: Planets Kepler-56b And Kepler-56c Will Be Swallowed Whole By Host Star |work= International Business Times |author= Charles Poladian |date= 2014-06-03 |accessdate= 2017-09-07 }}
{{cite simbad |title= KOI-1241.02 | accessdate=2017-09-07 }}
}}
Further reading
- {{cite journal |journal= Mon. Not. R. Astron. Soc. |volume= 428 |issue= 2 |pages= 1077 |date= 20 August 2012 |first1= Jason H |last1= Steffen |first2= Daniel C |last2= Fabrycky |first3= Eric |last3= Agol | display-authors= etal |title= Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability |doi= 10.1093/mnras/sts090 |doi-access= free |bibcode= 2013MNRAS.428.1077S |arxiv= 1208.3499 }}
External links
- {{cite web |url= http://kepler.nasa.gov/Mission/discoveries/kepler56b/ |archive-url= https://web.archive.org/web/20150926173357/http://kepler.nasa.gov/Mission/discoveries/kepler56b/ |url-status= dead |archive-date= 2015-09-26 |title= Kepler-56b |publisher= kepler.nasa.gov |accessdate= 2016-01-02 }}
- {{cite web |url= http://futurism.com/star-swallows-not-one-but-two-exoplanets-2014/ |title= Star to Swallow not One, but Two Exoplanets |author= Megan Smith |date= 8 June 2014 |publisher= Futurism LLC |access-date= 2 January 2016 |archive-date= 9 March 2016 |archive-url= https://web.archive.org/web/20160309124913/http://futurism.com/star-swallows-not-one-but-two-exoplanets-2014/ |url-status= dead }}
Category:Exoplanets discovered in 2012
Category:Exoplanets discovered by the Kepler space telescope
{{exoplanet-stub}}