mardi 23 septembre 2008

Serpens 3


Alpha Serpentis (α Ser / α Serpentis) is a triple star system in the constellation Serpens, in its head (Serpens Caput). Alpha Serpentis also has the traditional names Unukalhai (Unukalhay, Unuk al Hay, Unuk Elhai, Unuk), from the Arabic عنق الحية ʿunuq[u] al-ħayya[h] meaning "[the] neck", and Cor Serpentis, a Latin phrase meaning "the heart of the serpent". Alpha Serpentis is approximately 73.2 light years from Earth.
The primary star, Alpha Serpentis A is an orange K-type giant with an apparent magnitude of +2.63. It has a total luminosity of 70 times solar and a surface temperature of 4300 kelvins. The radius of the star is some 15 times as large as that of the Sun. The magnitude +11.8 Alpha Serpentis B is 58 arcseconds from the primary, and the 13th magnitude Alpha Serpentis C lies 2.3 arcminutes from A.


Eta Serpentis (η Ser / η Serpentis) is a binary star in the constellation Serpens. It carries the seldom used traditional name Tang (Mandarin 唐朝 - Táng Cháo), after the Tang Imperial Dynasty.
The primary, Eta Serpentis A is an orange K-type giant with an apparent magnitude 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 from Earth.


Mu Serpentis (μ Ser / μ Serpentis) is a star in the constellation Serpens, in its head (Serpens Caput). It is sometimes called by the name Leiolepis (Greek λειολεπις), meaning "smooth scaled".
Mu Serpentis is a white A-type main sequence dwarf with an apparent magnitude of +3.54. It is approximately 156 light years from Earth.


Xi Serpentis (ξ Ser / ξ Serpentis) is a triple star system in the constellation Serpens. In the past, it was called by the traditional name Nehushtan (Hebrew נחושתן), which refers to the bronze serpent of Moses. When King Hezekiah destroyed the bronze serpent, opponents of Hezekiah protested by memorializing the serpent among the summer stars, with Ophiuchus representing Hezekiah, and Serpens representing Nehushtan. The opponents thought that destroying such a highly treasured bronze artifact, through which their God Yahweh performed a saving miracle, was an attack on Israelite-Hebrew history and heritage.
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 arcseconds from the primary pair. Xi Serpentis is approximately 105 light years from Earth.


Beta Serpentis (β Ser / β Serpentis) is a star system in the constellation Serpens, in its head (Serpens Caput). It also has the traditional name Chow, from the Mandarin 周, zhōu, referring to the Zhou Dynasty. Beta Serpentis is approximately 153 light years from Earth and is a member of the Ursa Major Moving Group.
The primary component, Beta Serpentis A, is a white A-type main sequence dwarf with an apparent magnitude of +3.65. It has two companions, the magnitude +9.9 B, 31 arcseconds distant, and the magnitude +10.7 C, 201 arcseconds away.


Delta Serpentis (δ Ser / δ Serpentis) is a star system in the constellation Serpens, in its head (Serpens Caput). It also has the traditional name Qin or Chin, from the Mandarin 秦朝, Qín Cháo, referring to the Qin Dynasty. It is approximately 210 light years from Earth. The light from the four stars in the system give a combined apparent magnitude of +3.80(combined).
The system consists of a pair of binary stars separated by 66 arcseconds. The primary component, Delta Serpentis A, is a yellow-white F-type subgiant with an apparent magnitude of +4.2. It is classified as a Delta Scuti type variable star and its magnitude varies by 0.04 with a period of 0.134 days. Its binary companion, Delta Serpentis B, is also a F-type subgiant which is slightly dimmer, with a magnitude of +5.2. A and B are separated by four arcseconds on the sky, and perform one orbit around their centre of mass once every 3200 years. The 14th magnitude stars Delta Serpentis C and 15th magnitude Delta Serpentis D form the second binary sub-system. They are separated from each other by 4.4 arcseconds.


Theta Serpentis (θ Ser / θ Serpentis) is a star system in the constellation Serpens. It is approximately 132 light years from Earth. Theta Serpentis also has the traditional name Alya, or Alga, which is derived from an Arabic term meaning "the fatty tail" of an Oriental breed of sheep.
Both Theta-1 Serpentis and Theta-2 Serpentis are white A-type main sequence dwarfs. θ¹ has an apparent magnitude of +4.62 while the slightly dimmer θ² has a magnitude of +4.98. These two stars are 22 arcseconds apart on the sky, putting them at least 900 Astronomical Units apart with an orbital period of at least 14,000 years. Both stars are similar to each other in all respects, having luminosities of 18 and 13 times solar respectively, radii of about twice solar and also masses of roughly 2 times that of our Sun. Both star have a surface temperature of 8,000 kelvins.
The third star in the system, Theta Serpentis C is a yellow G-type star with an apparent magnitude of +6.71. It is separated by 7 arcminutes from θ².
Alya
Al-Alyah
The fatty tail of a sheep
الألية

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