[ it is located 70 light years from the Sun. It is moving closer to the Sun with a radial velocity of −9 km/s.[7]]This is an Am star[25] on the main-sequence with a stellar classification of kA2hA5mA7 V.[4] This notation indicates the spectrum displays the calcium K-line of an A2 star, the hydrogen lines of an A5 star, and the metal lines of an A7 star.[27] It has been examined for the presence of a magnetic field, but the detected level was not statistically significant.[28]
Epsilon Serpentis has an estimated 1.82 times the mass of the Sun and 1.78 times the Sun's radius.[12] The star is radiating 12[12] times the Sun's luminosity from its photosphere at an effective temperature of around 7,928 K.[15] It is a candidate for an infrared excess at a wavelength of 25 μm, suggesting a circumstellar disk of dust with a temperature of {{Val|250|70|u=K}} may be orbiting roughly 4.2 AU from the host star.[32] The star is around half[12] a billion years old and is spinning with a projected rotational velocity of 33.1 km/s.[15]
Etymology
Epsilon Serpentis was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines".[35] along with α Ser (Unukalhai), δ Ser, δ Oph (Yed Prior), ε Oph (Yed Posterior), ζ Oph and γ Oph.[36]
According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, al-Nasaq al-Yamānī or Nasak Yamani were the title for two stars :δ Ser as Nasak Yamani I and ε Ser as Nasak Yamani II (exclude α Ser, δ Oph, ε Oph, ζ Oph and γ Oph).[37]
In Chinese, {{lang|zh|天市右垣}} ({{lang|zh-Latn|Tiān Shì Yòu Yuán}}), meaning Right Wall of Heavenly Market Enclosure, refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of ε Serpentis, β Herculis, γ Herculis, κ Herculis, γ Serpentis, β Serpentis, α Serpentis, δ Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi.[1] Consequently, ε Serpentis itself is known as {{lang|zh|天市右垣八}} ({{lang|zh-Latn|Tiān Shì Yòu Yuán bā}}, {{lang-en|the Eighth Star of Right Wall of Heavenly Market Enclosure}}), represent the state Ba (巴) (or Pa).[39][2][3]
References
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2. ^{{zh icon}} AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 24 日
3. ^{{zh icon}} English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name {{webarchive |url=https://web.archive.org/web/20100810114313/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#HeavenlyMarketEnclosure |date=August 10, 2010 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.
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