Gamma Leonis

Starbox begin
name=Gamma Leonis A/B Starbox image


caption= Starbox observe
epoch=J2000
ra=10^h 19^m 58.3^s
dec=+19° 50′ 30″
appmag_v=1.98 (2.28/3.51)
constell=Leo Starbox character
class=K0 IIIb / G7 III
b-v=1.14
u-b=1.00
variable= Starbox astrometry
radial_v=−36.8
prop_mo_ra=310.77
prop_mo_dec=−152.88
parallax=25.96
p_error=0.83
absmag_v=−0.92 Starbox detail
mass=?
radius=23/10
luminosity=180/50 | temperature=4,470/4,980
metal= 30% Sun
rotation=
age= Starbox catalog
names=Algeiba, 41 Leo, BD +20°2467, HD 89484, LTT 12764/12765, GCTP 2423.00, SAO 81298, ADS 7724, HIP 50583. Starbox reference
Simbad=HD+89484

Gamma Leonis (γ Leo / γ Leonis) is a binary star system in the constellation Leo. It also has the traditional name Algieba or Al Gieba.

Name origin and history

The name "Algieba" originates from the Arabic "Al-Jabhah", meaning "the forehead". Despite this meaning, the star actually appears in the mane of Leo. The star's Latin name is "Juba".

*Algieba (gamma), Adhafera (Zeta Leonis), and Al Jabbah (Eta Leonis) have collectively been called the "Sickle".
*Algieba (gamma), along with Adhafera (zeta), Regulus (Alpha) and eta (Al Jabbah) are the 8th manzil, Al Jabhah, the "Forehead," promoting love, benevolence, and help against enemies.
*The Lion is associated with the Hebrew letter Kaph and the 11th Tarot Trump "Strength".

It is known as 軒轅十二 (the Twelfth Star of Xuanyuan) in Chinese. Xuanyuan is the name of Yellow Emperor.

ystem components

Algieba, as a binary system, consists of two stars. The brighter component has an apparent magnitude of +2.28 and is of spectral class K1-IIIbCN-0.5. The giant K star has a surface temperature of 4,470 K, a luminosity 180 times that of Earth's Sun, and a diameter 23 times that of the Sun. The companion star has an apparent magnitude of +3.51 and belongs to the spectral class G7IIICN-I. The giant G star has a temperature of 4,980 K, a luminosity of 50 times that of the Sun, and a diameter 10 times that of the Sun. With angular separation of just over 4", the two stars are at least 170 AU apart (four times the distance between Pluto and the Sun), and have an orbital period of over 500 years. Because the orbital period is so long, only a fraction of the full path has been observed since discovery.

Both stars are almost certainly true giants, meaning that they have stopped fusing hydrogen to helium in their cores and have expanded to great proportions. Although there has been too little observation of their orbit to calculate their masses, comparison with evolutionary calculations suggests that each are about double the mass of the Sun. Originating from the same interstellar cloud some two billion years ago, the stars have iron contents about a third that of the Sun. It is hard to tell how far along they might be in their life cycle. They both may be fusing helium in their cores, or they could be giants in development, with quiet helium cores that are waiting to fire up. The chemical composition at the surface, which is influenced by age, suggests the former.

ky appearance

The bright binary system in Leo with orange-red and yellow / greenish-yellow components visible through a modest telescope under good atmospheric conditions. To the eye, the Algieba system shines at mid-second magnitude, but a telescope easily splits the pair.

External links and references

* [http://www.astro.uiuc.edu/~kaler/sow/algieba.html Article from University of Illiniois at Urbana-Champaign]
* [http://www.winshop.com.au/annew/Algieba.html Online constellation reference]
* [http://www.daviddarling.info/encyclopedia/A/Algieba.html Astronomical Reference from Author David Darling]