Lyra
The constellation Lyra (the Lyre) already formed part of Ptolemy's list of 48 constellations and is also one of the 88 modern constellations approved by the IAU. Lyra isn't very big but still easily to be found because of its principal star Vega which is also a vertex of the so-called "Summer Triangle".
Beginning at the north, Lyra is surrounded by the Dragon Draco, the Roman hero Hercules, the Little Fox Vulpecula and the Cygnus the swan.
Notable features
Here are some of Lyra's brighter stars:
- α Lyr (Vega): with an apparent brightness of 0.03m this is the second brightest star of the northern hemisphere (after Arcturus) and the fifth brightest star all in all; its spectral class is A0 V and it lies at a distance of merely 25.3 ly. Actually it is a multiple star system (5 components). It was the first star to be photographed.
- β Lyr (Sheliak): a group of eclipsing binaries is named after this variable star (3.45m, spectral class B8 II), the Beta-Lyrae-stars.
- γ Lyr (Sulafat): the main star of this multiple star system is of magnitude 3.24m and spectral class B9 III
- δ Lyr: double star consisting of a blue-white star of 6m and a semi-regular red giant varying between 4m and 5m.
- ε Lyr: well known quadruple star, also called "Double Double" because each of the components is in itself yet another double star.
- ζ Lyr: another double star which can be split using binoculars.
- RR Lyr: lent its name to a whole type of pulsating variable stars, the RR Lyrae-stars.
Notable deep sky objects
- M56: a rather loose globular cluster at a distance of approximately 32,900 ly with a diameter of about 85 ly. Its apparent brightness is 8.3m.
- M57: also known as the "Ring Nebula", this is one of the best known of all planetary nebulae (8.8m; age between 6,000 and 8,000 years).
Mythology
Older maps of the sky show a bird, especially a vulture (Vultur cadens). Together with Cygnus and Altair this constellation then represents the Stymphalian Birds killed by the Greek hero Heracles (Roman Hercules) during his Sixth Labour.
Lyra is better known as the lyre, however, the musical instrument invented by the Greek god Hermes. Hermes gave it to his half-brother Apollo who passed it on to Orpheus. Orpheus went into the Underworld to find and rescue his bride Eurydice who had been killed by a snake-bite. Hades (Roman Pluto) was deeply moved by Orpheus' music, so much in fact that he agreed to let Eurydice leave with Orpheus. On one condition, however: Orpheus must walk in front of his bride and not look back while still in the Underworld. At the last moment Orpheus could no longer restrain himself and did what had been prohibited thus condemning Eurydice. After Orpheus' death his lyre was placed among the stars.
Lyra is also one of the two protagonists in Philip Pullman's His Dark Materials trilogy. Her full name is Lyra Belacqua, but her surname becomes changed to Silvertongue. She is the daughter of Asriel Belacqua and Marisa Coulter.
