BalompiÃ© de la universidad

History

Like all the constellations of the Zodiac, the Lion has very old origins. Mentioned by Ptolémée in its Almageste , it would correspond in the Greek Mythologie to the lion of Némée killed by Hercules at the time of the first of its twelve work.

One can note that the constellation close to the Chevelure of Bérénice was formerly regarded as a simple asterism in the Lion before being detached about it.

Observation of stars

; Localization of the constellation The Lion can be localized starting from the Grande Ourse, by taking the alignment of two internal stars to the " casserole". This alignment falls on Alpha Leonis (Régulus).

The Lion is contrary to the Taureau compared to the Gemini, on the axis which passes then by α Virginis.

Locally, the Lion can recognize itself directly by its general form, and if the conditions of visibility are good, by the form of the " faucille" who forms his head.

; Form constellation The form in which the Lion appears depends much on the conditions of visibility.

The first four visible stars (Mag 2,5) form a very flattened trapezoid, with in the contrary direction of the needles of a watch Régulus (α Leo) in South-west, the base of the front legs, Algeiba (γ1 Leo) a little more in North (the neck), Zosma (δ Leo) in the North-East (the base of the tail) and Denebola (β Leo) in the East (the end of the tail).

When the conditions are better (Mag 4), one sees taking shape the " faucille" on the basis of Régulus (α Leo), which passes by η, γ (Algeiba), ζ, μ and mends towards the South with ε Leo. This " faucille" mark the head of the Lion, whose muzzle is prolonged a little towards the West with κ (northern) and λ (southern) Leo, which is visible only under very good conditions (Mag 4.5).

With optimal conditions, the forms South-eastern side are better visible. θ Leo is quite visible in the South of δ Leo (Zosma), on alignment between Régulus and Dénébola. The leg behind is marked by ι and σ Leo, the other leg back is completed either on χ Leo, or on σ Leo, nearer to Régulus. On its side, the leg before is completed on ο Leo.

Principal stars

Regulus (α Leonis)

The most brilliant star of the constellation of the Lion names Régulus (α Leonis), which means “ the Latin Kinglet ” in (It was also known under the name of Cor Leonis , the “ Cœur of the Lion ”). With a Magnitude connect of 1,36, it acts of the 21e the most brilliant star of the sky.

Régulus is a star of the principal Séquence, 4 times broader and more massive than the Sun. Being a white star, it is much hotter than this last and 130 times more brilliant.

It has small a companion, distant of 4.200 astronomical Unité. This one is itself doubles.

Régulus is almost in the field of the ecliptic . It has an ovoid form, probably secondary with the importance of the centrifugal force due at a number of important revolutions (period = 16:00).

Denebola (β Leonis)

Denebola (β Leonis), the 2nd star of the constellation, whose name means “ the Tail of the Arab Lion ” in , is a white star of a diameter and an about double mass of those of the Sun, relatively near to the Solar system (36 light-years).

It is also a variable star class δ Scuti and its magnitude oscillates very légèremement around 2,14.

Other stars

Several other less luminous stars of the Lion were named, such Algieba (γ¹ Leo), Zosma (δ Leo), Close-cropped Elased Australis (ε Leo), Adhafera (ζ Leo), Chort or Coxa (θ Leo), Al Minliar Al Asad (κ Leo), Alterf (λ Leo), Close-cropped Elased Borealis (μ Leo) and Subra (ο Leo).

The stars α, η, γ, ζ, μ and ε Leonis constitute the Astérisme called “the Sickle”.

Wolf 359 is a Naine red, 50 000 times less luminous than the Sun. It is about the 6th star nearest to our Solar system (4th if one regards the sytème Alpha of the Centaur as only one object). Distant 7,78 years light, its absolute magnitude is only of 16,55 what is the object of it less the brilliance known in the vicinity of the Solar system.

Celestial objects

The Lion contains several Galaxie S brilliant whose twins M65 and M66 between ι and θ Leonis, and M95 and M96 9° in the east of Régulus, are the most famous representatives. M65 and M66 are two distant spiral galaxies of 27 million years light and which seem to be gravitationally dependant. M95 and M96, two spiral galaxies là-aussi, are distant from 29 million years light and constitute a small cluster with several other less brilliant galaxies.

One also finds the elliptic Galaxie there M105, the spiral galaxies NGC 2903, NGC 3370 and NGC 3521. Just in the north of Régulus, Leo I and Leo II belong to our local Groupe.

See too

List of stars of the Lion

Random links:

Jeanne of Leon | Acétazolamide | Marginella desjardini | .au | Bernard Esambert