ζ Virginis
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Zeta Virginis (ζ Virginis, abbreviated Zeta Vir, ζ Vir) is a
binary star 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 ...
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 ...
of
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, ...
. It is visible to the naked eye with an
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 +3.376 and is located about a half degree south of the
celestial equator The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. By extension, it is also a plane of reference in the equatorial coordinate system. Due to Earth's axial tilt, the celestial ...
. Based on
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 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 and distances of ...
mission, it is about distant from the
Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
. The two components are designated Zeta Virginis A (officially named Heze , a mid-20th-century name for the system) and B.


Nomenclature

''ζ Virginis'' ( Latinised to ''Zeta 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 components as ''Zeta Virginis A'' and ''B'' 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). Zeta Virginis bore the name ''Heze'' in a 1951 publication, ''Atlas Coeli'' ( Skalnate Pleso Atlas of the Heavens), by Czech astronomer Antonín Bečvář. Its origin is unknown. 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 ''Heze'' for the component Zeta Virginis A on 1 June 2018 and it is now so included in the List of IAU-approved Star Names. In Chinese, (), meaning ''
Horn Horn may refer to: Common uses * Horn (acoustic), a tapered sound guide ** Horn antenna ** Horn loudspeaker ** Vehicle horn ** Train horn *Horn (anatomy), a pointed, bony projection on the head of various animals * Horn (instrument), a family ...
(asterism)'', refers to an asterism consisting of ζ Virginis and
Spica Spica is the brightest object in the constellation of Virgo and one of the 20 brightest stars in the night sky. It has the Bayer designation α Virginis, which is Latinised to Alpha Virginis and abbreviated Alpha Vir or α Vir. Analys ...
. 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 ζ Virginis is (, ).


Properties

The primary, ζ Virginis A, is a
main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...
star with a
spectral class In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...
A3 V, indicating that it is generating energy through the
nuclear fusion Nuclear fusion is a nuclear reaction, reaction in which two or more atomic nuclei combine to form a larger nuclei, nuclei/neutrons, neutron by-products. The difference in mass between the reactants and products is manifested as either the rele ...
of hydrogen at its core. This energy is being radiated from its outer envelope at an
effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...
of 8,247 K, giving it the white hue of an
A-type star A type or type A may refer to: Science * A-type asteroid, a type of relatively uncommon inner-belt asteroids * A type blood, a type in the ABO blood group system * A-type inclusion, a type of cell inclusion * A-type potassium channel, a type of ...
. It has twice the mass of the Sun and double the
Sun's radius Solar radius is a unit of distance used to express the size of objects in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: 1\,R_ = 6.957\ti ...
and is about a half billion years old. The star was confirmed by Jan Ovidiu Tercu and Gabriel Cristian Neagu as a variable of DSCT type. The variability has an amplitude of 0.009 magnitudes and a main period of 0.097112 d. Other observed periods are 0.439, 1.069, 0.07691 and 0.07433 d. The variability was discovered during the datamining activity with the goal of increasing the student's investigative competences. In 2010, a low mass stellar companion was discovered - Zeta Virginis B. Though it has not been under observation for a sufficient length of time to determine accurate orbital elements, it is estimated to be
orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...
ing at an average separation of at least 24.9  AU with an
orbital eccentricity In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values be ...
of 0.16 or more and
orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...
of a minimum of 124 years. This companion may be a
red dwarf A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs are ...
star, which would explain the observed
X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...
flux from this system.


References

{{DEFAULTSORT:Zeta Virginis Virginis, Zeta Virgo (constellation) A-type main-sequence stars
Heze Heze (), formerly known as Caozhou, is the westernmost prefecture-level city in Shandong province, China, bordering Jining to the east and the provinces of Henan and Anhui to the west and south respectively.The total area is 12238.62 square kilo ...
Virginis, 079 066249 5107 118098 3792 Durchmusterung objects Binary stars