Lupus (the Wolf) is a southern constellation located between Centaurus and Scorpius. Although it lacks the instantly recognizable shape of neighboring constellations, it contains several bright blue-white stars and a remarkable collection of deep-sky objects.
Its best-known attraction is SN 1006, the remnant of a supernova that became extraordinarily bright in the year 1006 and may have been the brightest stellar explosion ever recorded by human observers.
Lupus is also one of the 48 constellations cataloged by the Greek astronomer Ptolemy in the second century AD, although its original identity was that of an unspecified wild animal rather than necessarily a wolf.
History and Mythology of Lupus
The stars of Lupus were recognized in antiquity, but the animal they represented was not always identified as a wolf.
In ancient Greek astronomy, the figure was associated with a wild animal held by the neighboring constellation Centaurus, often depicted as being carried toward Ara, the Altar. The Greek term Therion meant a wild animal or beast, reflecting the uncertainty over its precise identity.
Ptolemy included the constellation in his Almagest during the second century AD, and later astronomical traditions gradually established the Latin name Lupus, meaning wolf.
Unlike constellations associated with a particular mythological hero, Lupus is best understood through its relationship with Centaurus and Ara, which together formed a recognizable scene in ancient celestial illustrations.
Where Is Lupus and When Can You See It?
Lupus is the 46th-largest constellation, covering approximately 334 square degrees of the southern sky. It lies between Centaurus and Scorpius, bordering Centaurus, Circinus, Hydra, Libra, Norma, and Scorpius.
The best time to observe Lupus is May through July, particularly June, when it is well placed in the evening sky. The constellation is most easily seen from the Southern Hemisphere, where its brighter stars can be identified under reasonably dark skies. From tropical northern latitudes, much of Lupus appears low in the southern sky, but it is not visible in its entirety from Britain.
To locate Lupus, begin with the bright stars of Centaurus and look toward Scorpius. Lupus occupies the region between them, with its brightest stars forming a loose pattern rather than a distinctive geometric shape.
Notable Stars in Lupus
- Alpha Lupi – The brightest star in Lupus, a hot blue-white giant approximately 460 light-years away. It shines at magnitude 2.3 and is roughly ten times as massive as the Sun. Alpha Lupi is a Beta Cephei variable star, undergoing small, regular changes in brightness caused by pulsations within the star.
- Beta Lupi – The constellation’s second-brightest star, a blue-white giant approximately 380 light-years away, with an apparent magnitude of 2.7. It is a massive, relatively young star that can be seen without optical equipment.
- Gamma Lupi – A blue-white star system approximately 420 light-years away, shining at a combined magnitude of 2.8. Its bright primary star is accompanied by another star, making it an interesting multiple-star target.
- Delta Lupi – A hot blue-white star with an apparent magnitude around 3.2. Like several of the brighter stars in Lupus, it belongs to a young population of massive stars associated with the wider Scorpius–Centaurus region.
- Eta Lupi – A blue-white star system shining at approximately magnitude 3.4. It is a useful reference point for locating the nearby globular cluster NGC 5986.
Lupus also contains several fainter stars of astronomical interest, including the young variable star RU Lupi, which is still surrounded by material associated with its formation.
Notable Deep-Sky Objects in Lupus
Lupus contains no Messier objects, but its position near the Milky Way provides a variety of star clusters, nebulae, and one particularly important supernova remnant.
SN 1006 — The Brightest Recorded Supernova
SN 1006 is the remnant of a supernova first observed around May 1, 1006 AD.
The explosion became brighter than Venus and was reportedly visible during daylight. Historical accounts survive from observers in Asia, the Middle East, and Europe, making it one of the best-documented astronomical events of the medieval period. At its peak, SN 1006 may have reached an apparent magnitude around −7.5, although its exact brightness remains uncertain.
The remnant lies approximately 7,000 light-years away and is now observed as an expanding shell of gas produced by a Type Ia supernova, an explosion involving a white dwarf star. Modern X-ray observations reveal the shock waves and high-energy particles produced as the debris expands into surrounding space.
Although the remnant is extremely faint visually, it has become an important target for astronomers studying supernova explosions and cosmic-ray acceleration.
Read more in SN 1006: The Brightest Supernova in Recorded History.
NGC 5986 — A Globular Star Cluster
NGC 5986 is a globular cluster approximately 34,000 light-years away, located near Eta Lupi. It shines at an apparent magnitude around 7.5 and contains a dense population of old stars bound together by gravity.
Under dark skies, the cluster can be detected with binoculars or a small telescope as a faint, rounded glow. Larger telescopes begin to resolve its brighter outer stars.
NGC 5986 is particularly interesting because it contains evolved stars that provide clues about the later stages of stellar evolution.
Retina Nebula — IC 4406
The Retina Nebula (IC 4406) is a planetary nebula formed when an aging star expelled its outer layers into space. Its unusual rectangular appearance comes from our viewing angle toward a more complex, roughly cylindrical structure.
Detailed images from the Hubble Space Telescope reveal dark lanes of dust running across the glowing gas, giving the nebula its distinctive resemblance to the retina of an eye.
The Retina Nebula is faint and difficult to observe visually, but it is a striking target for astrophotography.
Other Star Clusters in Lupus
Several additional star clusters are worth exploring:
- NGC 5822 – A relatively bright open cluster containing a loose collection of stars.
- NGC 5824 – A distant, densely concentrated globular cluster.
- NGC 5927 – A globular cluster located toward the rich star fields of the southern Milky Way.
These objects provide a mixture of open and globular clusters for observers with binoculars and telescopes.