Iota Virginis (ι Virginis, abbreviated Iota Vir, ι Vir) 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 ...

in the

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 ...

Virgo Virgo may refer to: *Virgo (astrology), the sixth astrological sign of the zodiac *Virgo (constellation), a constellation *Virgo Cluster, a cluster of galaxies in the constellation Virgo *Virgo Stellar Stream, remains of a dwarf galaxy *Virgo Supe ...

. Its apparent magnitude is 4.08. Based on its

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 ...

, it is assumed to be relatively nearby, at . Its two components are designated Iota Virginis A (officially named Syrma , the traditional name for the system) and B.

Nomenclature

''ι Virginis'' ( Latinised to ''Iota Virginis'') 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 two components as ''Iota 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. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speak ...

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). It bore the traditional name ''Syrma'', derived from the

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

سرما (تطريز ''sirmā'' "train (of a garment)". In 2016, the

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 approved the name ''Syrma'' for Iota Virginis on 12 September 2016 and it is now so included in the List of IAU-approved Star Names. For such names relating to members of

multiple star systems 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, ...

, and where a component letter (from e.g.

Washington Double Star Catalog The Washington Double Star Catalog, or WDS, is a catalog of double stars, maintained at the United States Naval Observatory. The catalog contains positions, magnitudes, proper motions and spectral types and has entries for (as of June 2017) 141,7 ...

) is not explicitly listed, the WGSN says that the name should be understood to be attributed to the brightest component by visual brightness. In China, (), meaning ''

Neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

'', refers to an asterism consisting of this star, Kappa Virginis,

Phi Virginis Phi Virginis (φ Virginis, abbreviated Phi Vir, φ Vir) is a binary star in the zodiac constellation of Virgo. It can be seen with the naked eye, having an apparent visual magnitude of +4.81. Based upon parallax measurements obtained duri ...

and

Lambda Virginis Lambda Virginis (λ Virginis, abbreviated Lambda Vir, λ Vir) is a binary star system in the zodiac constellation of Virgo. With an apparent visual magnitude of 4.5, it is bright enough to be seen with the naked eye. Based upon parallax ...

.AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 28 日
/ref> Consequently, Iota Virginis itself is known as (, en, the Second Star of Neck).

Properties

Iota Virginis is an

astrometric binary 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 ...

. The secondary regularly perturbs the primary, causing the latter to wobble around its

barycenter In astronomy, the barycenter (or barycentre; ) is the center of mass of two or more bodies that orbit one another and is the point about which the bodies orbit. A barycenter is a dynamical point, not a physical object. It is an important conc ...

. A preliminary

orbit In celestial mechanics, an orbit 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 object or position in space such as a p ...

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 55 years has been calculated. Iota Virginis A is a yellow-colored 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 ...

of F7IV-V. This star has 1.5 times 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 ...

, 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 16 km s⁻¹. It is radiating 8.7 times the

luminosity of the Sun 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 s ...

from its outer atmosphere 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 6,282 K. The radius is about 2.5 times that of the Sun. Iota Virginis B has not been directly detected, but based on its mass () it may be a

main-sequence star 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 Hert ...

or a

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...

. That star is also responsible for the drifting

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

of the primary. In 2011, it was noticed that the faint K-type main-sequence star HD 125354 had a similar

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

throughout space, and was likely physically associated. Another 2015 paper supported this hypothesis. The star, which is located away from Iota Virginis, also has a similar distance from the Sun, within the margin of error. It itself is a close binary with another star separated 0.33″ from the main star.

References

{{DEFAULTSORT:Iota Virginis Virginis, Iota Virgo (constellation) F-type subgiants Syrma Astrometric binaries Virginis, 099 069701 5338 124850 Durchmusterung objects el:Σύρνα