HR 4523 (66 G. Centauri) is a

binary star A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

system that is located in the northeastern part of the

Centaurus Centaurus is a bright constellation in the southern sky. One of the 88 modern constellations by area, largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one o ...

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

, at a distance of about from the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...

. The larger member of the system is a G-type star that is smaller than 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 ...

but of similar mass. It has a

common proper motion This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outsid ...

companion that was discovered by W. J. Luyten in 1960. This M-type star appears to be in a wide orbit around the primary at a current separation of about 211

astronomical unit The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits t ...

s (AU), (or 211 times the separation of the Earth from the Sun). By comparison,

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

orbits at an average distance of 30 AU.

Description

The

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

for the primary star in this system is G2V; the same as the Sun. That of the

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

companion is M4V. The primary star has an estimated 86% to 89% the

mass of the Sun The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

, 96% of the Sun's radius, and 85% of the

Sun's luminosity The solar luminosity (), is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal ...

. It is a slow rotator, with a

projected rotational velocity Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bulge ...

of 0.5 km/s. Age estimates range from 4.5 to 5.7 billion years (Gyr) up to 7.1 Gyr or 9.48 Gyr. Compared to the Sun, it only has about 52% of the abundance of elements other than hydrogen and helium; what astronomers term the

metallicity In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a ...

of a star. This star system has a relatively large proper motion. The HR 4523 system is presently located within the

Epsilon Indi Moving Group Epsilon Indi, Latinized from ε Indi, is a star system located at a distance of approximately 12 light-years from Earth in the southern constellation of Indus. The star has an orange hue and is faintly visible to the naked eye with an a ...

, although it gives itself away as an interloper, since the star is older and has a different composition than the group members. It has space velocity components = .

Planetary system

The primary star is believed to be orbited by a Neptune-like planet with a

minimum mass In astronomy, minimum mass is the lower-bound calculated mass of observed objects such as planets, stars and binary systems, nebulae, and black holes. Minimum mass is a widely cited statistic for extrasolar planets detected by the radial veloc ...

16 times that of the Earth. The orbital period of this planet is 122.1 days. No other planets have been discovered orbiting this star. While a 2013 study was unable to confirm this planet, it was confirmed by a 2023 study, with updated parameters. An examination of this system in the

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

did not reveal an excess emission that would otherwise suggest the presence of a circumstellar

debris disk A debris disk (American English), or debris disc (Commonwealth English), is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris dis ...

In popular culture

The

couch gag The opening sequence of the American animated television series ''The Simpsons'' is among the most popular opening sequences in television. It is accompanied by " ''The Simpsons'' Theme", one of television's most recognizable theme songs. The fi ...

for ''

Bart's Not Dead "Bart's Not Dead" is the thirtieth season premiere and 640th episode of the American animated television series ''The Simpsons''. In this episode, Bart fakes a miracle and is approached by a Christian filmmaker who wants to make an adaptation of ...

'' in the television series ''

The Simpsons ''The Simpsons'' is an American animated sitcom created by Matt Groening for the Fox Broadcasting Company. The series is a satirical depiction of American life, epitomized by the Simpson family, which consists of Homer, Marge, Bart, Lisa, ...

'' has an alien family sitting on a couch in this star system. The adult male alien asks why

Homer Homer (; grc, Ὅμηρος , ''Hómēros'') (born ) was a Greek poet who is credited as the author of the ''Iliad'' and the ''Odyssey'', two epic poems that are foundational works of ancient Greek literature. Homer is considered one of the ...

sounds like

Walter Matthau Walter Matthau (; born Walter John Matthow; October 1, 1920 – July 1, 2000) was an American actor, comedian and film director. He is best known for his film roles in '' A Face in the Crowd'' (1957), ''King Creole'' (1958) and as a coach of a ...

References

External links

* {{DEFAULTSORT:HD 102365 G-type main-sequence stars HR, 4523 Planetary systems with one confirmed planet M-type main-sequence stars Binary stars Centaurus CD-39 07301 0442 Centauri, 66 102365 057433 4523