BD+20 594b
{{Short description|Extrasolar planet in the constellation Aries}}
{{Infobox planet
| name = BD +20° 594 b
| discovery_site = Kepler Space Observatory, La Silla, Chile
| discovered = 2016
| discovery_method = Transit
| apsis = astron
| semimajor = 0.241 {{±|0.019|0.017}} AU
| period = 41.6855 {{±|0.0030|0.0031}} d
| inclination = {{val|89.55|+0.17|-0.14}}
| star = BD+20°594
| mean_radius = {{val|2.23|+0.14|-0.11}} {{Earth radius|link=y}}
| mass = 16.3 {{±|6.0|6.1}}{{cite web| url = http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=k2-56+b&type=CONFIRMED_PLANET | title = CONFIRMED PLANET OVERVIEW PAGE | website = NASA Exoplanet Archive | publisher = NASA | access-date = 2016-08-11}} {{Earth mass|link=y}}
| density = {{val|7.890|+3.400|-3.100}} g cm−3
| single_temperature = {{convert|546|K|C F}} {{±|19|18}} K
}}
BD+ 20° 594b (also known as K2-56b) is a massive exoplanet discovered by the Kepler spacecraft in collaboration with the HARPS spectrometer at La Silla in Chile.
Naming
BD+20 594b indicates that the planet circles a star found in the Bonner Durchmusterung catalogue, BD +20° 594, the 594th entry in the +20-degree zone (declinations from +19 to +20 degrees),{{cite web|url=http://vizier.u-strasbg.fr/cgi-bin/Dic-Simbad?BD|title=Dictionary of Nomenclature of Celestial Objects: Details on Acronym: BD|date=2020-09-20|website=SIMBAD|publisher=Centre de Données astronomiques de Strasbourg| url-status=live|archive-url=https://web.archive.org/web/20201006034506/http://cdsweb.u-strasbg.fr/cgi-bin/Dic-Simbad?BD| archive-date=2020-10-06}} and that it is the first planet discovered orbiting that star.
K2-56b indicates that the planet circles a star catalogued in the Kepler 2 mission catalogue (part of the extended K2 Kepler mission), the 56th one in the catalogue,{{cite web|url=https://exoplanetarchive.ipac.caltech.edu/docs/K2Numbers.html|title=K2 Confirmed Planet and Candidate Naming Policy|date=2022-01-24|website=NASA Exoplanet Archive|publisher=NASA|access-date=2024-05-09}} and that it is the first planet discovered orbiting that star.
Planet
With a radius of 2.2 R🜨 and a mass of 16.31 M🜨, BD+20594b is substantially smaller than Neptune.{{cite encyclopedia |url=https://exoplanet.eu/catalog/bd_20_594_b--2546/ |encyclopedia=Extrasolar Planets Encyclopaedia |title=Planet BD+20 594 b |date=2016 }} Taking the estimates of its radius and mass at face value, the composition of the planet would be rocky, hence making it classified as a mega-Earth. BD+20594b's exact composition is still unknown.
The planet was discovered on January 28, 2016 by astrophysicist Néstor Espinoza and his team from the Catholic University of Chile, using data from the two-wheeled Kepler mission (K2). It orbits a K-type star 496.08 light years away in the constellation Taurus.{{Cite journal |arxiv = 1601.07608|bibcode = 2016ApJ...830...43E|title = Discovery and Validation of a High-Density sub-Neptune from the K2 Mission|journal = The Astrophysical Journal|volume = 830|issue = 1|pages = 43|last1 = Espinoza|first1 = Néstor|last2 = Brahm|first2 = Rafael|last3 = Jordán|first3 = Andrés|last4 = Jenkins|first4 = James S|last5 = Rojas|first5 = Felipe|last6 = Jofré|first6 = Paula|last7 = Mädler|first7 = Thomas|last8 = Rabus|first8 = Markus|last9 = Chanamé|first9 = Julio|last10 = Pantoja|first10 = Blake|last11 = Soto|first11 = Maritza G|last12 = Morzinski|first12 = Katie M|last13 = Males|first13 = Jared R|last14 = Ward-Duong|first14 = Kimberly|last15 = Close|first15 = Laird M|year = 2016|doi = 10.3847/0004-637X/830/1/43|s2cid = 119118301 | doi-access=free }}
It is believed that planets with a radius greater than 1.6 times the Earth's are not usually rocky,{{Cite journal |arxiv = 1407.4457|bibcode = 2015ApJ...801...41R|title = Most 1.6 Earth-radius Planets are Not Rocky|journal = The Astrophysical Journal|volume = 801|issue = 1|pages = 41|last1 = Rogers|first1 = Leslie A|last2 = Brahm|first2 = Rafael|last3 = Jordán|first3 = Andrés|last4 = Jenkins|first4 = James S|last5 = Rojas|first5 = Felipe|last6 = Jofré|first6 = Paula|last7 = Mädler|first7 = Thomas|last8 = Rabus|first8 = Markus|last9 = Chanamé|first9 = Julio|last10 = Pantoja|first10 = Blake|last11 = Soto|first11 = Maritza G|last12 = Morzinski|first12 = Katie M|last13 = Males|first13 = Jared R|last14 = Ward-Duong|first14 = Kimberly|last15 = Close|first15 = Laird M|year = 2015|doi = 10.1088/0004-637X/801/1/41|s2cid = 9472389}} making BD+20594b an exception to this rule.
See also
References
{{reflist}}
External links
- [http://www.universetoday.com/127325/largest-rocky-world-found Largest Rocky World Found - Universe Today]
{{Exoplanet}}
{{2016 in space}}{{Taurus (constellation)}}{{sky|03|34|36.23|+|20|35|57.2|496.08}}
{{DEFAULTSORT:K2-56b}}
Category:Taurus (constellation)
Category:Exoplanets discovered in 2016
Category:Transiting exoplanets
Category:Exoplanets discovered by K2
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