Virgo

[m2q]

Virgo

(the Virgin; abbrev. Vir, gen. Virginis; area 1294 sq. deg.)

an equatorial zodiacal constellation which lies between

Leo and Libra, and culminates at midnight in mid-April.

Its origin dates back to Babylonian times and it has been

associated with numerous female deities, including Ishtar

(Babylonia), Isis (ancient Egypt), Demeter (ancient Greece)

and Astraea (ancient Rome). Its brightest stars were

catalogued by Ptolemy (c. AD 100–175) in the Almagest.

Virgo is the second-largest of the 88 constellations but

is not particularly prominent, save for its brightest star,

α Virginis (Spica or Azimech), magnitude 1.0. Other bright

stars include γ Virginis (Porrima), a fine binary with pale

yellow (F0) components, both magnitude 3.6 (combined

magnitude 2.7), separation 2.7, period 168.7 years (closest

2005), ε Virginis (Vindemiatrix or Almuredin), magnitude

2.9, ζ Virginis, magnitude 3.4, and δ Virginis, also

magnitude 3.4. There are five other stars of magnitude

4.0 or brighter.

There are no bright open star clusters or nebulae

in Virgo, but the constellation contains a large number

of galaxies, many of which are members of the Virgo

Cluster, which extends into neighboring Coma Berenices.

The brightest members of the Virgo Cluster are the giant

elliptical galaxies M49 (NGC 4472), 8th magnitude, and

M87(NGC4486,VirgoA), 9th magnitude, which is a strong

x-ray and radio source and from which emanates a jet of

material thought to have been expelled froma black hole at

its center. An interesting non-cluster galaxy is M104 (NGC

4594, the Sombrero Galaxy), an 8th-magnitude spiral with

a dark lane of obscuring dust presented almost edge-on.

The constellation also contains the first quasar to have

been detected (in 1963), 3C 273, magnitude 12.9.