Gamma Serpentis (γ Serpentis, γ Ser) is a star in the equatorial constellation Serpens, in the part of the constellation that represents the serpent's head (Serpens Caput). It has an apparent visual magnitude +3.85, which means it is visible to the naked eye. Based upon parallax measurements by the Hipparcos spacecraft, this star is approximately 36.7 light years from Earth.
Epoch J2000 Equinox J2000
|Right ascension||15h 56m 27.18269s|
|Declination||+15° 39′ 41.8206″|
|Apparent magnitude (V)||3.85|
|Spectral type||F6 V|
|U−B color index||-0.03|
|B−V color index||+0.48|
|Radial velocity (Rv)||6.78 ± 0.09 km/s|
|Proper motion (μ)|| RA: 310.93 ± 0.20 mas/yr |
Dec.: -1282.19 ± 0.18 mas/yr
|Parallax (π)||88.86 ± 0.18 mas|
|Distance||36.70 ± 0.07 ly |
(11.25 ± 0.02 pc)
|Absolute magnitude (MV)||3.60|
|Mass||1.30 ± 0.15 M☉|
|Radius||1.55 ± 0.05 R☉|
|Luminosity||3.02 ± 0.09 L☉|
|Surface gravity (log g)||4.23 cgs|
|Temperature||6,350 ± 310 K|
|Metallicity [Fe/H]||−0.19 dex|
|Rotational velocity (v sin i)||10.2 km/s|
Gamma Serpentis is an ordinary F-type main sequence star with a stellar classification of F6 V. It is larger and more massive than the Sun, with three times the solar luminosity. Based upon its mass, it may have a convection zone in its core region. The projected rotational velocity along the equator is 10.2 km/s. It is younger than the Sun with an estimated age of 3.5 billion years. The effective temperature of the star's outer atmosphere is 6,350 K, giving it the yellow-white-hued glow of an F-type star.
Occasionally Gamma Serpentis is listed as having two 10th magnitude companions, but it appears that these stars are just optical neighbours.
According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, al-Nasaq al-Sha'āmī or Nasak Shamiya were the title for three stars:β Ser as Nasak Shamiya I, γ Ser as Nasak Shamiya II, γ Her as Nasak Shamiya III (exclude β Her). The star was later given the proper name Ainalhai, from the Arabic عين الحية ‘Ayn al-Ḥayyah "the Serpent's Eye".
In Chinese, 天市右垣 (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 γ Serpentis, β Herculis, γ Herculis, κ Herculis, β Serpentis, δ Serpentis, α Serpentis, ε Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi. Consequently, the Chinese name for γ Serpentis itself is 天市右垣四 (Tiān Shì Yòu Yuán sì, English: the Fourth Star of Right Wall of Heavenly Market Enclosure), represent the state Zheng (鄭) (or Ching), together with 20 Capricorni (according to Ian Ridpath version) in Twelve States (asterism).
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