Carmilla

The Lyre is one of the 88 Constellation S. It is located in the northern hemisphere.

History

The Quadrant is an old constellation. Ancient civilizations in the Middle East and India saw a vulture there. The Greek Astronome S saw a Lyre there (or rather a “ will kithara ”) and the oldest sky charts represent it generally held in the claws of a vulture.

In the shape of a vulture, this constellation was hung up again with the legend of Hercules which, for its 6th work, killed the Oiseaux of the lake Stymphale. The constellation is besides close to the Cygne and the Aigle.

The quadrant would represent for its part the musical instrument of Orphée.

Observation of stars

; Localization of the constellation The constellation is recognized directly with its form: Véga is a very brilliant star, which recognizes by its association with two weaker stars (mag 3) β and γ Lyr, the unit evoking very clearly a club of golf. When the conditions of visibility are better, Véga is with the point of small a " V" who points out his name.

With more long distance, the constellation is on the alignment which leaves the Grande Ourse, according to the diagonal SOUNDS " casserole". This alignment passes by the heart of the Dragon and by its head, to come to touch Véga, then further Altaïr from the Aigle.

Véga is one of the tops of large the Triangle of summer, easily locatable by itself.

; Form constellation The constellation is dominated by Véga (α Lyr), and secondarily by the couple which forms the " club of golf": Sulafat (γ Lyr) most distant and slightly more brilliant than Sheliak (β Lyr), intermediary which forms the angle of the " club of golf".

When the conditions of visibility are better (mag 4), one sees that Véga is registered in the middle of the side (κ Lyr, 13 Lyr) of a quadrilateral drawn by Sulafat (γ Lyr, extremity of the club), κ Lyr, 13 Lyr and θ Lyr.

Under excellent conditions (mag 5), three parallel star couples take shape, and one sees the constellation in the shape of a butterfly whose Véga is the head, prolonged by ζ Lyr and δ Lyr which forms the body; the Southern wing is formed by κ Lyr in top and the couple Sulafat (γ Lyr) and Sheliak (β Lyr) in bottom; and the Northern wing is formed by 13 Lyr in top, and ν Lyr and θ Lyr in bottom.

; Alignments with long distance Véga is on the alignment which leaves the Grande Ourse, according to the diagonal SOUNDS " casserole". This alignment passes by the heart of the Dragon and by its head, to come to touch Véga, then further Altaïr from the Aigle. It passes by α from the Capricorne and both " pieds" Capricorn; and for the observers located sufficiently at the south, this alignment is prolonged to Al ir Na' (α Gruis).

Principal stars

Vega (α Lyrae)

Véga (α Lyrae), whose name means “the Arab vulture ” in , is the most brilliant star of the constellation of the Quadrant, and besides the 5th the most brilliant star of the sky. Approximately 3 times larger and more massive than the Sun, Véga are a white star 50 times more luminous than this one. It is rather close to the Solar system since it is distant only of 25 light-years.

With a Magnitude connect very close to zero (0,03), its color and its proximity made of it an ideal star for the observation and Véga was used as standard for the measurement of index “B-V” of the other stars, which determines with precision their color.

Because of the phenomenon of Precession of the equinoxes, Véga will take the place of current pole star, α Ursae Minoris in approximately 10.000 years. It is the most extreme position which the pole can have compared to its current location, the place of the poles is a circle whose diameter is appreciably the Vega segment - α Ursae Minoris.

Véga, with α Aquilae (Altair) and α Cygni (Deneb), form the Astérisme of the Triangle of summer.

Other stars

Sheliak (β Lyrae) - “ the Toothing-stone ” in Arabic - is the prototype of a class of variable stars known as variable of β type; Lyrae. It is in fact of the systems of double stars whose components eclipse mutually with regular intervals and who are sufficiently close one to the other to be seriously deformed by the Forces of tide. In the case of Sheliak, the two components Orbit NT in 12 days and project hot gas filaments regularly.

Sulafat (γ Lyrae) means “ the tortoise ” in Arabic. The quadrants of formerly could be made of a carapace of tortoise acting as case of resonance; Greek mythology tells that thus Mercure made its quadrant. From an astrophysical point of view, this blue giantess (Standard spectral A0) magnitude 3,2 is intrinsically 40 times more brilliant than Véga, itself - let us recall it - 50 times more brilliant than the Sun.

δ Lyrae is a triple star. The two first components are easily separable with binoculars and their beautiful blue and red contrasted colors are visible.

ε Lyrae is very known to be in fact a double double: ε¹ and ε ² are both of the double stars whose members are in the two cases separated by 140 ua. ε¹ and ε ² are distant approximately 10.000 ua and it is difficult to say if the two couples orbit really one around the other. The four stars are similar, of white stars approximately twice more massive than the Sun.

RR Lyrae is the prototype of a category of named pulsating variable stars variable of type RR Lyrae.

T Lyrae is a carbonaceous star (spectral Type C8) having the characteristic red color. Its magnitude varies slowly and irregularly from 7,8 to 9,6. It is located at 2° in the south-south-west of Véga.

Two other stars of the constellation bear a name: Aladfar (η Lyr) and Alathfar (μ Lyr).

HD 178911 and HD 177830 have each one at least a Exoplanète.

Celestial objects

The constellation of the Quadrant contains famous the Nébuleuse annular planet gear M57, also called “Nebulous of the ring”, halfway between β and γ Lyrae. The ring is in fact a gas cloud ejected by a central star. In spite of its celebrity, it is difficult to see with small a Télescope and the central star is invisible unless using large.

The Quadrant also contains the globular Amas M56 and the Galaxie NGC 6745.

See too

List of stars of the Quadrant

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