Eta Virginis (η Virginis, abbreviated Eta Vir, η Vir) is a

triple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally called a ''st ...

in the

zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course of the year. Within this zodiac ...

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 first constellati ...

Virgo Virgo may refer to: Arts and entertainment * Virgo (film), a 1970 Egyptian film * Virgo (character), several Marvel Comics characters * Virgo Asmita, a character in the manga ''Saint Seiya: The Lost Canvas'' * ''Virgo'' (album), by Virgo Four, ...

. From

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

measurements, it is about from the Sun. It has a combined

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of 3.89, bright enough to be seen with the naked eye in dark skies. The system consists of a binary pair designated Eta Virginis A together with a third companion, Eta Virginis B. A's two components are themselves designated Eta Virginis Aa (officially named Zaniah , the traditional name of the system) and Ab.

Nomenclature

''η Virginis'' ( Latinised to ''Eta Virginis'') is the system's

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

. The designations of the two constituents as ''Eta Virginis A'' and those of ''A's'' components - ''Eta Virginis Aa'' and ''Ab'' - 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. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally called a ''st ...

s, and adopted by the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

(IAU). It bore the traditional name ''Zaniah'' , derived from the

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

زاوية ''zāwiyah'' "corner", the same source as ''Zavijava'' (

Beta Virginis Beta Virginis, a name Latinised from β Virginis, is a star in the equatorial constellation of Virgo. It has the proper name Zavijava (), and, despite its designation 'beta', is the fifth-brightest star in Virgo with an apparent visual ...

). 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 catalogue 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 ''Zaniah'' for the component Eta Virginis Aa on 12 September 2016 and it is now so included in the List of IAU-approved Star Names. In the catalogue of stars in the ''Calendarium of Al Achsasi Al Mouakket'', this star was designated ''Thanih al Aoua'', which was translated into

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

as ''Secunda Latratoris'', meaning "the second barker". This star, along with Beta Virginis (Zavijava),

Gamma Virginis Gamma Virginis (γ Virginis, abbreviated Gamma Vir, γ Vir), officially named Porrima , is a binary star system in the constellation of Virgo. It consists of two almost identical main sequence stars at a distance of about 38 light-years ...

(Porrima),

Delta Virginis Delta Virginis (δ Virginis, abbreviated Del Vir, δ Vir), formally named Minelauva , is a star in the zodiac constellation of Virgo. With an apparent visual magnitude of 3.4, this star is bright enough to be seen with the naked eye. It i ...

(Minelauva) and

Epsilon Virginis Epsilon Virginis (ε Virginis, abbreviated Epsilon Vir, ε Vir), formally named Vindemiatrix , is a star in the zodiac constellation of Virgo. The apparent visual magnitude of this star is +2.8, making it the third-brightest member of Vi ...

(Vindemiatrix), were ''Al ʽAwwāʼ'', "the Barker". In

Chinese Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethnic ...

, (), meaning '' Left Wall of Supreme Palace Enclosure'', refers to an asterism consisting of Eta Virginis, Gamma Virginis, Delta Virginis, Epsilon Virginis and

Alpha Comae Berenices Alpha Comae Berenices (α Comae Berenices, abbreviated Alpha Com, α Com) is a binary star in the constellation of Coma Berenices ( Berenice's Hair), away. It consists of two main sequence stars, each a little hotter and more luminous ...

. Consequently, the

Chinese name Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethni ...

for Eta Virginis itself is (, .), representing (), meaning "The Left Law Administrator". 左執法 (Zuǒzhífǎ), spelled ''Tso Chih Fa'' by R.H. Allen, means "the Left-hand Maintainer of Law" Richard Hinckley Allen: Star Names — Their Lore and Meaning: Virgo
/ref>

Properties

Eta Virginis looks single, but lunar

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks f ...

s have shown it to be a very close

consisting of two stars 0.6 AU apart, assuming a distance of 91 parsecs, with a third slightly more distant star. The inner pair is a

spectroscopic binary A binary star or binary star system 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 as separate stars us ...

that completes an orbit in 72 days. The inclination of this orbit was determined through

interferometer Interferometry is a technique which uses the '' interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...

observations to be 45.5°, allowing the masses of the two stars to be estimated. The primary star, Eta Virginis Aa, has a mass about 2.5 times the

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

, while the secondary, Eta Virginis Ab, has 1.9 solar masses. The faint tertiary star, Eta Virginis B, orbits the inner group in a wider orbit over a period of 13.1 years. Eta Virginis is 1.97 degrees north of the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

, so it can be

occulted An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks f ...

by the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

and (rarely) by

planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...

s. On October 12, 272 BC the ancient Greek astronomer

Timocharis Timocharis of Alexandria ( or Τιμοχάρης, ''gen.'' Τιμοχάρους; c. 320–260 BC) was a Greek astronomer and philosopher. Likely born in Alexandria, he was a contemporary of Euclid. Work What little is known about Timocharis comes ...

observed a conjunction of the star with

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

. The last occultation by a planet took place on September 27, 1843, also by

, which will occult it again on September 30, 2078. Two degrees north-following of Eta Virginis is

SS Virginis SS Virginis is a semiregular variable star that appears with a strong red hue. It varies in apparent magnitude from a maximum of 6.0 to a minimum of 9.6 over a typical period of 361 days. Its spectral class is C63e, indicating that SS Vi ...

, a typical cool

carbon star A carbon star (C-type star) is typically an asymptotic giant branch star, a luminous red giant, whose Stellar atmosphere, atmosphere contains more carbon than oxygen. The two elements combine in the upper layers of the star, forming carbon monox ...

and one of the most red-colored stars in the equatorial sky.

References

External links

Zaniah
{{DEFAULTSORT:Eta Virginis Virginis, Eta Virgo (constellation) Triple star systems A-type main-sequence stars Zaniah Virginis, 015 060129 4689 107259 Durchmusterung objects