Virgo is one of the constellations of the zodiac in astronomy. Virgo is not one of the constellations that looks like what it represents – a maiden in this case– but it is relatively easy to find thanks to its bright star, Spica. Though it looks sparse in comparison to constellations like Taurus, Virgo is home to several notable deep sky objects and offers rich views if you are scanning the constellation with binoculars or a small telescope.
Virgo gets its name from the Latin word for virgin, which it only very loosely represents; marked by a few naked eye stars. You can find Virgo on in the spring and summer months in the northern hemisphere, or in fall and winter in the southern hemisphere. It is wedged between Leo to its west and Libra lying to the east. Northern hemisphere observers can also find Virgo by tracing it along the arc of the Big Dipper, then heading over to the star Arcturus in the constellation Boötes before reaching Spica along the same line. Other neighboring constellations include the constellations Boötes, Coma Berenices, Corvus, Crater, Hydra, and Serpens.
Virgo has the distinction of being the constellation in which the First Point of Libra, or the autumn equinox point, lies. This is one of two points where the celestial equator and the ecliptic cross (the other point is the First Point of Aries or the spring equinox point). The point was named for when it was first noted in the constellation Libra but is now in Virgo due to the precession of the equinoxes (how the Earth’s axis slowly changes orientation relative to the backdrop of stars).
History and Mythology of The Constellation Virgo
Virgo has always been viewed as a woman in some way or another since ancient times. The Babylonian’s recognized Virgo as far back as the 10th Century BC. They associated the constellation with the mythical goddess Shala together with an ear of grain. Grain traditionally signifies fertility in many cultures, so naturally, Virgo has also been linked with fertility. The Babylonian roots are still present in modern-day astronomy, as the star Spica gets its name from the Latin phrase for “ear of grain”.
The Sumerians had a similar interpretation of Virgo. To them the constellation was dubbed The Frond of Erua: so named since it represented the goddess Erua holding a palm leaf. Erua was the goddess of pregnancy and childbirth, so again the association between Virgo and fertility is clear.
Virgo’s correlation with grains is also present in ancient Greek culture, linking the constellation to Demeter, their goddess of wheat and agriculture. Some classical Greek interpretations saw Virgo as Erigone; Icarius’ tragic daughter. The Romans associated Virgo with their goddess of agriculture, Ceres.
Most of the constellations noted by the 2nd Century Astronomer Ptolemy are described In De Astronomica (or Poeticon Astronomicon), a book series commonly attributed to the Latin author Hyginus. Historians believe that in the book, Virgo is the representation of the mythological lady Parthenos: daughter of Apollo who died a maiden and was placed among the stars.
Beginning in the Middle Ages, Virgo was also sometimes associated with the Virgin Mary.
Stars in The Constellation Virgo
Virgo has several naked eye stars that mark the constellation’s outline. It’s the constellation which has the most stars housing known exoplanets, with almost 30 stars within the constellation possessing planets in their orbits.
- Spica or α Virginis/ Alpha Virginis is the brightest star in Virgo and also one of the brightest stars in the night sky. It is generally the 15th brightest star in the sky, but this varies sometimes due to variable stars and their changing brightness.
Spica has an apparent magnitude of 1.04. It is part of a close binary star system. Spica is a blue giant star, while its component is also a massive star lying about 260 light-years from Earth. This makes it one of the closest known stars massive enough and evolved enough to die in a Type II supernova event. The primary star in the system outshines the sun by about 12,000 times.
- Vindemiatrix or ε Virginis /Epsilon Virginis is the third brightest star in the constellation with a magnitude of 2.8. This giant star has a luminosity around 77 times that of the Sun.
- Heze or ζ Virginis/ Zeta Virginis is a main sequence star with a magnitude of approximately 3.4 and lying some 74 light-years from Earth.
- Zaniah or η Virginis/ Eta Virginis is part of a triple star system and easily visible to the naked eye. The system lies roughly 265 light-years from Earth. The triple systems is quite a close one, and therefore cannot be resolved in a telescope.
- 70 Virginis 70 Virginis is a magnitude 5 star only less than 59 light-years away. The star is host to an exo-planet which was discovered in 1996.
- χ Virginis or Chi Virginis is an orange giant star 294 light-years away with a magnitude of over 4.6. Chi Virginis is yet another binary star found in Virgo. What makes it even more interesting is the massive planet discovered in its orbit in 2009. The exo-planet has a mass at least 11 times that of Jupiter.
- 61 Virginis 61 Virginis is a yellow main sequence dwarf star almost 28 light-years from the solar system. The star is significant since it’s almost identical in composition to the Sun albeit less massive, and is the first well-established star of this type which may house a Super Earth: an exo-plant more massive than Earth but much less massive than Uranus or Neptune.
- Other stars to note within the constellation Virgo are Gamma Virginis, Iota Virginis, Mu Virginis, 109 Virginis, Nu Virginis.
Notable Deep-Sky Objects Found In Virgo
A cluster of galaxies called the Virgo Cluster lies within the constellation’s borders, so Virgo is exceptionally rich in galaxies and other deep sky objects including a large number of Messier Objects. Here are a few of the more notable deep sky objects within the constellation.
- Virgo Cluster is a cluster of galaxies stretching across the constellations Coma Berenices and Virgo. The Virgo Cluster’s centre is located about 53.8 million light years away from the Solar System. The cluster is believed to contain as many as 2000 galaxies.
- Messier 49 or NGC 4472 was the first galaxy discovered in the Virgo Cluster, likely because it is also the brightest galaxy in the cluster. The elliptical galaxy has a magnitude of 9.4 making it a perfect target using amateur instruments. It is located about 56 million light-years away and was discovered in 1771. Astronomers have observed the galaxy gravitationally interacting with the small dwarf galaxy UGC 7636. M49 is notable for several other reasons: it is host to at least 5900 globular clusters, all with an average age of 10 billion years. The galaxy also contains a known supernova.
- Another really bright galaxy in the Virgo Cluster is Messier 58 or NGC 4579; a barred spiral galaxy with a magnitude of 10.5. It lies around 62 million light-years from Earth. Two supernovae have been discovered in M58.
- Messier 87 is the largest galaxy in the Virgo cluster and a bright radio source. It is found some 60 million light-years from the Solar System. Its central supermassive black hole spews out jets of electrons which are visible in several different wavelengths making it of particular interest to the study of black holes.
- The Sombrero Galaxy or M104 is probably one of the most photogenic galaxies in the night sky. It is even a great target for amateur astrophotographers. The edge-on spiral galaxy lies 28 million light-years from Earth. The galaxy has a prominent dust lane and its distinct central bulge is made up of older stars.
- Galaxy NGC 4438 is a type of active galactic nucleus object lying 50 million light-years from Earth. Its supermassive black hole is also ejecting streams of matter.
- NGC 4261 is located at a distance of 45 million light-years from Earth and is exceptionally radio-bright.
- IC 1101 is a giant elliptical galaxy in the Abell 2029 Cluster. It is one of the largest known galaxies in the universe – more than 50 times greater than the size of the Milky Way. It also lies very far away from Earth at just over 1 billion light-years away.
- Messier 60 or NGC 4649 is also an elliptical galaxy in the Virgo Cluster and another great telescope target since it’s the third brightest elliptical galaxy. It has a magnitude of 9.8. M60 lies some 55 million light-years from the Sun and is home to a supernova discovered in it in 2004.
- Messier 61 or NGC 4303 is a spiral galaxy belonging to the Virgo Cluster. It has an apparent magnitude of just over 10 and can clearly be seen through small telescopes. The galaxy lies about 52.5 million light-years away and contains six supernovae discoveries.
- Messier 84 or NGC 4374 is a lenticular galaxy with a disk of quickly rotating gas and stars. It is also the home of two supernovae discoveries.
- Messier 86 or NGC 4406 is another lenticular galaxy near the center of the Virgo Cluster. It was discovered in 1781. It’s easily visible in binoculars and small telescopes with a visual magnitude of just under 10; and is one of the brightest known radio sources.
- 3C 273 was the first quasar ever identified, and this makes sense since it is also the brightest and most luminous quasar as seen from Earth. It lies about 2.5 billion light-years away, which actually makes it one of the closest quasars to the Milky Way.
- Virgo is abundant in exo-planets. There are at least 35 verified exo-planets in orbit around almost 30 stars in the constellation.
Virgo Meteor Showers
Several meteor showers emanate from Virgo, mostly from late January to mid-May. Included are the Alpha Virginids, Gamma Virginids, Eta Virginids, Iota Virginids, Mu Virginids, Pi Virginids, and March Virginids among others. Many have a low peak rate – the Eta Virginids has a rate of only one or two meteors per hour. The Alpha Virginids can reach a rate of 10 meteors per hour, and typically peak in the first half of April.
At first glance, Virgo seems to be nothing more than a collection of a handful of naked eye stars, with Spica being its most notable feature. Bringing out binoculars or a telescope reveals that Virgo is packed with targets that are both interesting and beautiful to view.