Antlia is a faint southern sky constellation that was created by French astronomer Abbé Nicolas Louis de Lacaille during his 1751–52 expedition to South Africa. The constellation’s brightest star is Alpha Antliae, an orange giant 365 light years away with a visual magnitude of just 4.28.
Antlia is the 62nd biggest constellation in the sky, and is visible to observers located between +45° and -90° of latitude, although best seen in late winter and spring. This dim constellation is located south of Hydra, with its other neighboring constellations including Centaurus, Hydra, Pyxis, and Vela.
Lacaille Constellation Family
Antlia is a member of the Lacaille family of constellations, together with Caelum, Circinus, Fornax, Horologium, Mensa, Microscopium, Norma, Octans, Pictor, Reticulum, Sculptor, and Telescopium.
During the 18th century, French astronomer Abbé Nicolas Louis de Lacaille set up an observatory in South Africa in order to study the southern sky. He subsequently named his 14 new constellations, with the exception of Mensa, after instruments of science and art, with Antlia representing an air pump.
– Alpha Antliae, the constellation’s brightest star, is an orange giant situated 365 light years distant whose magnitude varies between 4.22 and 4.29. This roughly one billion year old star is 53 times bigger than the Sun, 2.2 more massive, and around 500 times more luminous.
– Epsilon Antilae, the second brightest star in Antlia, is an orange giant 700 light years away that shines with an apparent magnitude of 4.51. It is around 37 times bigger than our sun, and 1,279 times brighter.
– Iota Antilae, the constellation’s third brightest star, is an orange giant located 199 light years away from our solar system that has an apparent magnitude of 4.60.
Other notable stars of interest in Antlia includes the binary star systems of Theta Antliae and Eta Antliae; the double star Delta Antliae; and the irregular variable star U Antliae, whose apparent magnitude of 5.5 varies in brightness by as much as 1.6.
Notable Deep Sky Objects
There are no Messier objects in Antlia, but it does contain several faint galaxies, including the spiral galaxies IC 2560 and NGC 3244; a pair of interacting galaxies called IC 2545; and the starburst galaxy NGC 3125.
– NGC 2997, the brightest galaxy in Antlia, is an unbarred spiral galaxy found 24.8 million light years distant that shines with a magnitude of just 10.6. It also provides an example of a grand design galaxy, meaning its spiral arms are clearly defined, unlike 90% of all other spiral galaxies. It has a yellow colored nucleus, while its spiral arms are notable for their distinctive ionized hydrogen clouds where stars are forming. There are hundreds of billions of stars contained in NGC 2997.
– The Antlia Cluster (Abell S0636) consists of around 234 individual galaxies located 133.4 million light-years distant. Dominating its northern subgroup is NGC 3268, while the southern subgroup centres around NGC 3258, with both giant elliptical galaxies containing thousands of globular clusters. The Antlia Cluster is the third nearest galaxy cluster to our Local Group, with just the Fornax Cluster and the Virgo Cluster nearer.