Mu Arae d, also known as HD 160691 d, formally named Rocinante , is an

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

orbiting the

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

Mu Arae Mu Arae (μ Arae, abbreviated Mu Ara, μ Ara), often designated HD 160691, officially named Cervantes , is a main sequence G V star, G-type star approximately 50 light-years away from the Sun in the constellation of Ara (constellation), A ...

of the constellation

Ara ARA may refer to: Media and the arts * American-Romanian Academy of Arts and Sciences * '' Artistička Radna Akcija'', compilation album released in former Yugoslavia * Associate of the Royal Academy, denoting membership in the British Royal Aca ...

Characteristics

The planet has a mass about half that of

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

and orbits at a

distance Distance is a numerical or occasionally qualitative measurement of how far apart objects or points are. In physics or everyday usage, distance may refer to a physical length or an estimation based on other criteria (e.g. "two counties over"). ...

of 0.921 AU from the star with a period of 310.55 days. The planet may be located at a distance close enough to the star to receive a comparable amount of

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

radiation as the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

does from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. However, it is too close to the star to be able to support

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, a ...

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

at its surface. Furthermore, given its mass, the planet is likely to be a

gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...

with no

solid Solid is one of the State of matter#Four fundamental states, four fundamental states of matter (the others being liquid, gas, and Plasma (physics), plasma). The molecules in a solid are closely packed together and contain the least amount o ...

surface.

Name

In July 2014 the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

launched

NameExoWorlds NameExoWorlds (also known as IAU NameExoWorlds) is the name of various projects managed by the International Astronomical Union (I.A.U.) to encourage names to be submitted for astronomical objects, which would later be considered for official ad ...

, a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Rocinante for this planet. The winning name was submitted by the Planetario de Pamplona,

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

Rocinante Rocinante () is Don Quixote's horse in the two-part 1605/1615 novel ''Don Quixote'' by Miguel de Cervantes. In many ways, Rocinante is not only Don Quixote's horse, but also his double; like Don Quixote, he is awkward, past his prime, and ...

was the

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million y ...

of the lead character of the novel ''

El Ingenioso Hidalgo Don Quixote de la Mancha is a Spanish epic novel by Miguel de Cervantes. Originally published in two parts, in 1605 and 1615, its full title is ''The Ingenious Gentleman Don Quixote of La Mancha'' or, in Spanish, (changing in Part 2 to ). A founding work of Western ...

''.

References

Ara (constellation) Exoplanets discovered in 2006 Giant planets Exoplanets detected by radial velocity Exoplanets with proper names Giant planets in the habitable zone {{extrasolar-planet-stub