Eta Serpentis is a binary star

Binary star

A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...

 in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Serpens

Serpens

Serpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....

. The primary, Eta Serpentis A, is an orange K-type

Stellar classification

In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...

 giant

Giant star

A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...

 with an apparent magnitude

Apparent magnitude

The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...

 of +3.23. It has a distant 12th magnitude companion, Eta Serpentis B, 3 arcminutes away. The Eta Serpentis star system is approximately 61.8 light years

Light Years

Light Years is the seventh studio album by Australian recording artist Kylie Minogue. It was released on 25 September 2000 by Parlophone and Mushroom Records. The album's style was indicative of her return to "mainstream pop dance tunes"....

 from Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

.

Name

In Chinese astronomy

Chinese astronomy

Astronomy in China has a very long history, with historians considering that "they [the Chinese] were the most persistent and accurate observers of celestial phenomena anywhere in the world before the Arabs."...

, the star is known as , meaning 'Left Wall of Heavenly Market Enclosure

Heavenly Market enclosure

Tian Shi Yuan, the Heavenly Market Enclosure , is one of the San Yuan or Three enclosures. Stars and constellations of this group are visible during late summer and early autumn in the Northern Hemisphere . The summer triangle lies directly to the northwest.-Asterisms:The asterisms are :...

'; the name refers to an asterism that represents eleven old states in China. The leftmost borderline of the enclosure consists of η Serpentis, δ Herculis

Delta Herculis

Delta Herculis is a fourth-magnitude star in the constellation Hercules. It has the traditional name Sarin....

, λ Herculis

Lambda Herculis

Lambda Herculis is a star inthe constellation Hercules.It has the traditional name Maasym .In Chinese, , meaning Left Wall of Heavenly Market Enclosure, refers to an asterism which is represent eleven old states in China which is marking the left borderline of the enclosure, consisting of λ...

, μ Herculis

Mu Herculis

Mu Herculis is a nearby star system about 27.1 light years from Earth in the constellation Hercules. Its main star, Mu Herculis A is fairly similar to the Sun although more highly evolved with a...

, ο Herculis

Omicron Herculis

Omicron Herculis is a multiple star system in the constellation Hercules. It has the traditional name Atia and the Flamsteed designation 103 Herculis.- Properties :...

, 112 Herculis, η Ophiuchi

Eta Ophiuchi

Eta Ophiuchi, also known as η Oph or η Ophiuchi, is a star in the constellation Ophiuchus. It also has the traditional name Sabik....

, ζ Aquilae

Zeta Aquilae

Zeta Aquilae is a triple star system in the constellation Aquila. It has the traditional names Deneb el Okab, from an Arabic term ذنب العقاب ðanab al-cuqāb meaning "the tail of the falcon", and the Mandarin names Woo and Yuë, derived from and represent the state Wu , an old state was located at...

, θ¹ Serpentis, ν Ophiuchi

Nu Ophiuchi

Nu Ophiuchi is a Class K0, third-magnitude star in the constellation Ophiuchus. Its closest stellar neighbour is the bright binary system Tau Ophiuchi, roughly 16.9 light years away from the star...

 and ξ Serpentis

Xi Serpentis

Xi Serpentis is a triple star system in the constellation Serpens. The primary star, Xi Serpentis A, is a yellow-white F-type giant with an apparent magnitude of +3.54. It is a spectroscopic binary with an orbital period of 2.29 days. A 13th magnitude companion, Xi Serpentis B, is located 25...

. Consequently, η Serpentis itself is known as , possibly a reference to the East China Sea

East China Sea

The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...

.