Ara, the Altar, is an ancient southern constellation lying in the Milky Way just south of the tail of Scorpius, its stars rich in distant giants.
At a glance
| stars in the figure | 8 |
|---|---|
| nearest star of the figure | Delta Arae, 198 light-years (60.7 pc) |
| farthest star of the figure | Gamma Arae, 1,110 light-years (341 pc) |
| depth | the farthest is 5.6 × farther than the nearest |
Read off the piece’s own catalogue, the same values it draws with.
About Ara
Ara is one of the constellations catalogued by Ptolemy. In Greek myth it was the altar on which the gods swore their alliance before the war against the Titans, and the Milky Way above it was pictured as the smoke rising from its fire. From the Mediterranean it barely clears the southern horizon, which is why its stars carry few traditional names.
The figure is a compact group of moderately bright stars. Several are orange giants, and Alpha Arae is a hot blue star spinning fast enough to have thrown off a disc of gas. Because Ara lies along the band of the Milky Way, its fields are crowded with background stars and clusters, among them Westerlund 1, one of the most massive young star clusters known in the Galaxy, heavily dimmed by dust.
What you see in the piece
Seen from space the altar has no shape. Delta Arae is the nearest of its stars and Gamma Arae lies far beyond the rest, deep towards the inner Galaxy, so the figure stretches into a long, thin spray of stars.
Questions
Where is Ara in the sky?
Ara lies south of the tail of Scorpius, in the Milky Way. It is best seen from the southern hemisphere on winter evenings, which are summer evenings in the north, where it stays very low or below the horizon.
How far away are the stars of Ara?
The nearest star of the figure is Delta Arae, 198 light-years (60.7 pc) away, and the farthest is Gamma Arae, 1,110 light-years (341 pc).