Delta Sagittarii (δ Sagittarii, abbreviated Delta Sgr, δ Sgr), formally named Kaus Media , is a double star in the southern

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 apparent path of the Sun across the celestial sphere over the course of the year. The pat ...

constellation of Sagittarius. The

apparent 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 lig ...

of this star is +2.70, making it easily visible to the naked eye. Parallax measurements place the distance at roughly 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 ...

Properties

Eggleton and Tokovinin (2008) list Delta Sagittarii as a binary star system consisting of an

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

K-type

giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

with a stellar classification of K3 III, and 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 ...

companion. The giant is a weak

barium star Barium stars are spectral class G to K stars whose spectra indicate an overabundance of s-process elements by the presence of singly ionized barium, Ba II, at λ 455.4 nm. Barium stars also show enhanced spectral features of carbon, the ...

, most likely having had its surface abundance of s-process elements enhanced through mass transfer from its orbiting companion. It has an estimated 3.21 times the mass of the Sun and is about 260million years old. Delta Sagittarii has three dim visual companions: * a 14th magnitude star at a separation of 26 arcseconds, * a 15th magnitude star at a separation of 40 arcseconds, and * a 13th magnitude star at a separation of 58 arcseconds from the primary.

Nomenclature

''δ Sagittarii'' ( Latinised to ''Delta Sagittarii'') is the star's Bayer designation. It bore the traditional names ''Kaus Media'', ''Kaus Meridionalis'', and ''Media'', which derive from the ar, قوس, rtl=yes ('bow') and la, media ('middle'). In 2016, 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 ...

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's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Kaus Media'' for this star. In the catalogue of stars in the ''Calendarium'' of

Al Achsasi al Mouakket Muḥammad al-Akhṣāṣī al-Muwaqqit ( ar, محمد الاخصاصي الموقت) was an Egyptian astronomer whose and catalogue of stars, ('Pearls of brilliance upon the solar operations'), was written at Cairo about 1650. Al-Akhsasi was a s ...

, this star was designated , meaning 'second of Warida'. In

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twe ...

, (' Winnowing Basket') refers to an asterism consisting of Delta Sagittarii, Gamma² Sagittarii,

Epsilon Sagittarii Epsilon Sagittarii ( Latinised from ε Sagittarii, abbreviated Epsilon Sgr, ε Sgr), formally named Kaus Australis , is a binary star system in the southern zodiac constellation of Sagittarius. The apparent visual magnit ...

and Eta Sagittarii. 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 ofte ...

for Delta Sagittarii itself is ('the Second Star of Winnowing Basket'). This star, together with Gamma Sagittarii, Epsilon Sagittarii, Zeta Sagittarii,

Lambda Sagittarii Lambda Sagittarii ( Latinized from λ Sagittarii), formally named Kaus Borealis , is a star in the southern constellation of Sagittarius. The star marks the top of the Archer's bow. Properties With an apparent visual magnitude of ...

, Sigma Sagittarii,

Tau Sagittarii Tau Sagittarii (Tau Sgr, τ Sagittarii, τ Sgr) is a star in the southern zodiac constellation of Sagittarius. Description With an apparent visual magnitude of +3.3, this is one of the brighter members of the constellati ...

and Phi Sagittarii, comprises the

Teapot A teapot is a vessel used for steeping tea leaves or a herbal mix in boiling or near-boiling water, and for serving the resulting infusion which is called tea. It is one of the core components of teaware. Dry tea is available either in tea ba ...

asterism. In

Hindu astrology Jyotisha or Jyotishya (from Sanskrit ', from ' “light, heavenly body" and ''ish'' - from Isvara or God) is the traditional Hindu system of astrology, also known as Hindu astrology, Indian astrology and more recently Vedic astrology. It is one ...

, this star is also called .

References

External links

Kaus Media information on Stars site
{{DEFAULTSORT:Delta Sagittarii K-type giants Barium stars White dwarfs Binary stars Sagittarii, Delta Sagittarius (constellation) Kaus Media Sagittarii, 19 089931 6859 168454 Durchmusterung objects