Zeta Piscium (ζ Piscium, abbreviated Zet Psc, ζ Psc) is a quintuple

star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speak ...

in the

zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the Sun path, apparent path of the Sun across the celestial sphere over the course of the year. ...

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 ...

Pisces Pisces may refer to: * Pisces, an obsolete (because of land vertebrates) taxonomic superclass including all fish * Pisces (astrology), an astrological sign * Pisces (constellation), a constellation **Pisces Overdensity, an overdensity of stars in ...

. Based upon

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

measurements obtained during the

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial obj ...

mission, it is located roughly distant 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 ...

. The system consists of 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 ...

(Zeta Piscium A) and a

triple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a ''star cluster'' or ''galaxy'', although, broadly speaking, ...

(BC), the latter consisting of a

spectroscopic binary A binary star is a system of two star, stars that are gravity, 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 separa ...

(B) and a single star (C). A's two components are themselves designated Zeta Piscium Aa (officially named Revati ) and Ab; B's two components as Ba and Bb. As the star system is 0.21° south of the

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...

, it can be

eclipsed In chemistry an eclipsed conformation is a conformation in which two substituents X and Y on adjacent atoms A, B are in closest proximity, implying that the torsion angle X–A–B–Y is 0°. Such a conformation can exist in any open chain, ...

( occulted) by the

moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, when close to or at one of its two

nodes In general, a node is a localized swelling (a "knot") or a point of intersection (a Vertex (graph theory), vertex). Node may refer to: In mathematics *Vertex (graph theory), a vertex in a mathematical graph *Vertex (geometry), a point where two ...

of its orbit; and is eclipsed by the sun from about 8-10 April.

Nomenclature

''ζ Piscium'' ( Latinised to ''Zeta Piscium'') is the system's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

. The designations of the three constituents as ''Zeta Piscium A'', ''B'' and ''C'', and those of ''A's'' and ''B's'' components - ''Zeta Piscium Aa'', ''Ab'', ''Ba'' and ''Bb'' - derive from the convention used by the Washington Multiplicity Catalog (WMC) for

multiple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speaki ...

s, and adopted by 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 ...

(IAU). The system is identified with ''

Revati Revati (रेवती) is a goddess featured in Hindu scriptures. She is the daughter of King Kakudmi and the consort of Balarama, the elder brother of Krishna, and one of the Dashavatara. Her account is given within a number of Hindu texts su ...

'' (रेवती ''rēvatī'', ), one of the Indian

nakshatra Nakshatra ( sa, नक्षत्रम्, translit=Nakṣatram) is the term for lunar mansion in Hindu astrology and Indian Astronomy. A nakshatra is one of 27 (sometimes also 28) sectors along the ecliptic. Their names are related to a ...

(

lunar mansion Often called lunar mansion, a lunar station or lunar house is a segment of the ecliptic through which the Moon passes in its orbit around the Earth. The concept was used by several ancient cultures as part of their calendrical system. Stations in ...

s). In 2016, the IAU organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name ''Revati'' for the constituent Zeta Piscium A on 30 June 2017 and it is now so included in the List of IAU-approved Star Names. Where a component letter is not explicitly listed, the WGSN says that the name should be understood to be attributed to the brightest component by visual brightness (component ''Aa'' in this case). In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

, (), meaning '' Outer Fence'', refers to an asterism consisting of Zeta Piscium,

Delta Piscium Delta Piscium (δ Piscium) is a solitary, orange-hued star in the zodiac constellation of Pisces. It has an apparent visual magnitude of +4.4, so it is bright enough to be faintly visible to the naked eye. Based upon an annual parallax ...

Epsilon Piscium Epsilon Piscium (Epsilon Psc, ε Piscium, ε Psc) is the Bayer designation for a star approximately away from the Earth, in the constellation Pisces. It is a yellow-orange star of the G9 III or K0 III spectral ty ...

Mu Piscium Mu Piscium (μ Piscium) is a solitary, orange-hued star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.84. Based upon an annual parallax shift of 10.73 mas as se ...

, Nu Piscium,

Xi Piscium Xi Piscium (ξ Piscium) is an orange-hued binary star system in the zodiac constellation of Pisces. In 1690, the astronomer Johannes Hevelius in his ''Firmamentum Sobiescianum'' regarded the constellation Pisces as being composed ...

and

Alpha Piscium Alpha Piscium (α Piscium) is a binary star system in the equatorial constellation of Pisces. Based upon parallax measurements made by the Hipparcos spacecraft, it is about from the Solar System. The two components are designated ...

. Consequently, the

Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are often a ...

for Zeta Piscium itself is (, en, the Third Star of Outer Fence.)AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日
/ref>

Properties

The primary, Zeta Piscium A, is a pair of A-type

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution of ...

stars with an

angular separation Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in pa ...

of 0.15

arcseconds A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...

and

visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

5.28. The secondary, Zeta Piscium B, is a

with a

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

of 9.075 days and an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

of 0.04. Together, components Ba and Bb have a combined visual magnitude of 6.43 and lie at an angular separation of 22.9 arcseconds from the primary. They are a F-type

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

star and a G-type main sequence star, respectively. The tertiary and fifth component, Zeta Piscium C, is a magnitude 12.2 star at an angular separation 1.0 arc seconds from component B. Together the star system has an apparent magnitude of +4.9.John Pratt's stars
re-publication by Dr J.P. Pratt (Doctor of Astronomy, University of Arizona) of sidereal coordinate data. Note: possibly a non-book published source.

References

{{DEFAULTSORT:Zeta Piscium Pisces (constellation) Piscium, Zeta A-type subgiants F-type main-sequence stars G-type main-sequence stars Durchmusterung objects Piscium, 086 007344/45 005737/43 0361/0362 5

Nomenclature

Properties

See also

References