Ara is a small inconspicuous constellation in the southern hemisphere. Derived from the Latin word for ‘altar’, it was once considered part of Centaurus and Lupus. However, it became separated when the modern constellation Norma was created by Lacaille in the 1750s. Ptolemy had charted this constellation in the 2nd century. It belongs to the Hercules family of constellations and is clearly visible at 9 Pm in the month of July.
The major stars in Ara are:
- Arae (Beta Arae): It is basically an orange K–type giant, which is around 603 light years away. Arae has a visual magnitude of about 2.84 and is the brightest star in the constellation.
- Arae (Alpha Arae): It is the second brightest star in the constellation with a visual magnitude which varies between 2.76 and 2.90. Alpha Arae is about 240 light years away from the earth.
- Arae (Gamma Arae): It is a blue–white B–type super giant, which is around 1,140 light years away. Gamma Arae has a visual magnitude of 3.5.
- Arae (Zeta Arae): Zeta Arae is an orange K–type giant and is around 574 light years away. Zeta Arae has a visual magnitude of 3.12.
- Arae (Mu Arae): It is around 50 light years away and has a visual magnitude of about 5.12.
- Arae (Epsilon Arae): It is a binary star system. Epsilon–1 is about 300 light years away with a visual magnitude of 4.06 and is an orange K–type giant. Epsilon–2 is a binary star, situated about 85.9 light years away. It has a visual magnitude of 5.27.
The deep sky objects in the constellation include:
- NGC 6193: It is a large open cluster which contains 27 stars. The estimated age of NGC 6193 is about 3 million years. It has a visual magnitude of 5.2 and is about 4,300 light years away from the earth.
- NGC 6397: NGC 6397 is a bright globular star located three degrees to the northwest of Beta Arae. NGC 6397 contains about 400,000 stars. It is about 7,200 light years away.
- The Stingray Nebula (Hen 3-1357): Stingray Nebula is a planetary nebula, approximately 18,000 light years away from the earth. Even though it is significantly smaller than most planetary nebulae, it is about 130 times larger than our solar system.
Ara lies in the third quadrant of the southern hemisphere and can be seen at latitudes between +25° and -90°. The brightest star in this constellation is about 603 light years away from the earth.
Ara is among the smaller constellations which occupies an area of 237 square degrees.
Ara is surrounded by constellations like Apus, Corona Australis, Norma, Pavo, Scorpius, Telescoipum and Triangulum Australe.
According to one of the myths, Ara represented an altar on which Zeus and other gods vowed to defeat the Titans and overthrow Cronus who ruled the Universe by deposing his father Uranus. The prophecy imprecated that the same fate would befall him and his own children would defeat him. To prevent it from happening, Cronus started swallowing all his sons until the youngest child Zeus was kept hidden by his mother Rhea. Zeus made Cronus vomit all his brothers and sisters and they all swore to overthrow Cronus and the Titans. The gods won in the end and Zeus became the god of the sky and placed the altar among the stars to commemorate god’s victory. However, another myth narrates the Ara representing the altar of Lycaon, the king of Arcadia who decided to test Zeus by serving him a meal of a dismembered child and later tried to kill him while he was asleep. This infuriated Zeus and he transformed Lycaon into a wolf and killed his 50 sons with lightning bolts.
