Ara (constellation)

Ara (Latin: "The Altar") is a southern constellation situated between Scorpius and Triangulum Australe. Ara (Greek: Βωμός) was one of the 48 Greek constellations described by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical Union. The orange supergiant Beta Arae is the brightest star in the constellation, with an apparent magnitude of 2.85—marginally brighter than the blue-white Alpha Arae. Seven star systems are known to host planets. The sunlike star Mu Arae hosts four known planets, while Gliese 676 is a binary red dwarf system with four known planets. The Milky Way crosses the northwestern part of Ara.