Lyra (“lyre”) is one of the smaller constellations, taking up an area of just 286 sq/deg in the northern sky between latitudes +90 and -40 degrees. It does, however, contains the 5th brightest star in the sky, Vega, which also forms part of the famous asterism of stars known as the Summer Triangle. Amongst other many spectacular astronomical objects contained within Lyra is the beautiful Ring Nebula, as well as nine stars with confirmed planets. Lyra is the 52nd biggest constellation, and is visible in the northern hemisphere from April to December, and in the southern hemisphere in winter.
Hercules Family of Constellations
It is part of the Hercules Family of constellations which contains 19 members, namely Hercules, Sagitta, Aquila, Lyra, Cygnus, Vulpecula, Hydra, Sextans, Crater, Corvus,Ophiuchus, Serpens, Scutum, Centaurus, Lupus, Corona Australis, Ara, Triangulum Australe, and Crux.
Lyra is taken to represent the lyre of Orpheus, a musician that is said to have been able to charm even stones with his music. In classical mythology, Orpheus was killed by the Bacchantes, and his lyre was cast into a river. Zeus however, sent an eagle to recover the lyre, and placed both the Lyre and the eagle among the stars.
– Vega (Alpha Lyrae), about 25 light years away, is the fifth most luminous star in the entire night sky (0.03 mag), and the second most luminous star in the northern skies. It is estimated to be only about 455 million years old, and has a spectral classification of A0V that makes it a white dwarf. It has just over twice the mass of the Sun, and is also a very fast spinner, with an equatorial rotational velocity of 274 km/s, which amounts to 86% of the velocity required to make it fly apart under its own centrifugal force. Around 12,000 BC, Vega was also the Pole Star, which it will be again in about 13,727 years’ time due to precession.
– Sulafat (Gamma Lyrae) is the second brightest star in Lyra (3.261 mag), and is a blue-white giant (B9 III) located around 620 light years from the Sun. Sulafat is about 15 times bigger than the Sun, twice as hot, and with a relatively fast rotational velocity of 72 km/s.
Notable Deep Sky Objects
– The Ring Nebula (M57, NGC 6720) is a perennial favourite among amateur star-gazers, since it is one of very few deep space objects that shows a hint of its true colour in good optics. Located about 2,300 light years away, the Ring Nebula has an apparent visual magnitude of 8.8, and is expanding at the rate of about 1 second of arc per 100 years.The Ring Nebula is a member of a class of nebulae known as bi-polar nebulae, because of the thick ring of material around its equator that greatly extends its structure through its main symmetrical axis. Look for M57 just south of the star Vega.
– Messier 56 (M56, NGC 6779) is a globular cluster located 32,900 light years distant, and stretching across 84 light years of space. It has an apparent magnitude of 8.3, and is an easy binocular target, lying between the stars Albireo and Sulafat, although you will need at least an 8-inch telescope and good seeing conditions to resolve its stars, of which about a dozen or so are variables.
– NGC 6745, also known as the Bird’s Head Galaxy, is a striking example of a galactic interaction that happened about ten billion years ago. The galaxy is located about 205 million light years away, and has an apparent visual magnitude of 13.3.
Three meteor showers are associated with Lyra, the Alpha Lyrids, the June Lyrids, and the Lyrids.
– The Lyrids, although not among the most spectacular meteor showers, does nevertheless have some things going for it, including being the longest known shower, with sightings of it dating back more than 2,600 years. The shower runs from about April 16 to April 26, with the maximum occurring on April 21st/22nd, when about 10 meteors per hour can be viewed, and occasionally more than 100 meteors.
– The June Lyrids usually runs from June 10th to June 21st, but only peaks at about 8 or so blue and white meteors per hour. The upside is that more than 30% of meteors leave fire and smoke trails, which makes this one of the more photogenic showers.
– The Alpha Lyrids is not a naked-eye shower. The best that can be expected is about one or two naked eye observations per hour, but binoculars can reveal as many as 18-33 meteors per hour at the peak that falls on July 14th.