Constellation Chart

As a far southern constellation, Ara is today almost invisible from Europe at any time of the year. Between 2,000 and 3,000 years ago, though, it was clearly visible from southern Europe and northern Africa during the summer months. The Greeks of that time called it Thytérion or Thysiastérion, the Altar of Sacrifice, perhaps because it rose in the sky at a propitious time of the year. This tradition was inherited by the Romans, who gave the constellation the name we know today: 'Ara' is the Latin word for 'Altar'.

Stars

There are few bright stars in this region of the sky. The two brightest, Alpha and Beta Arae, are coincidentally almost exactly the same magnitude of +2.8. Though the Beta star is almost 400 light years beyond the Alpha, it is much more luminous.

Some of Ara's stars are very distant: both Gamma Arae and Theta Arae lie more than 1,000 light years away, but both of these stars are brilliant supergiants, and so are clearly visible to the naked eye of an observer on Earth.

Star Clusters

The most notable cluster in Ara is a Globular group that lies somewhat 'below' the plane of the galactic disc. NGC 6397 is a fairly loose ball of stars lying approximately 7,000 light years (about 2,000 parsecs) from Earth's Solar System.

A little nearer to Earth, at about 4,500 light years distance, is an open star cluster, NGC 6193. This is quite a young cluster on a cosmic timescale, and still surrounded by much of its original nebulous material.

NGC6397

NGC6397 (Bennett 98, Caldwell 86) is a globular cluster located 2.9° north-east of Beta Arae. Described as bright (mag. 5.7), very large (26'), rich (but not especially so for a globular), it contains stars at mag. 10 and fainter.

NGC6362

NGC6362 (Bennett 95) is a nice globular cluster located near the far southern border of Ara, 1.2° north-east of Zeta Apodis, and 2.7.° south-west of Eta Pavonis. Described as quite bright (mag. 8.1), large (10.7'), and very gradually much brighter middle, well resolved, with stars of magnitude 14 to 17. Other sources indicate stars of mag. 12.5 and fainter. From the Digital Sky Survey. The bright star in the upper, right (north-west) corner shines at mag. 6.9, and is cataloged as GSC 9065:3654, or HIP 85668.

NGC6352

NGC6352 (Bennett 94, Caldwell 81) is an open cluster located 1.8° north-west of Alpha Arae. Described as fairly faint (mag. 8.2), and large (2'), it contains stars mag. 12 and fainter.

NGC6253

NGC6253 (Bennett 84) is a mag. 10 open cluster in western Ara described as small (5'), triangular, and containing (about 30) magnitude 13 stars. Epsilon-1 Arae lies 27' to the south.

NGC6193

NGC6193 (Caldwell 82) is a mag. 5.2 open cluster located 8.3° WNW of Alpha Arae, and 2.6° ESE of Epsilon Normae. Described as very large (15'), loose, and uncondensed, it contains about 30 stars mag. 6 and fainter. Dreyer mentions that a faint nebulosity is involved.

Henize 3

Astronomers have caught a peek at a rare moment in the final stages of a star's life: a ballooning shroud of gas cast off by a dying star flicking on its stellar light bulb. The Hubble telescope has captured the unveiling of the Stingray nebula (Hen-1357), the youngest known planetary nebula.

Twenty years ago, the nebulous gas entombing the dying star wasn't hot enough to glow. The Stingray nebula (Hen-1357) is so named because its shape resembles a stingray fish. Images of a planetary nebula in its formative years can yield new insights into the last gasps of ordinary stars like our Sun.

Planetary Destinations In Ara

Mu Arae

Parent Star: Mu Arae (HD 160691) (G3 IV-V) in the constellation of Ara is located at a distance of 49.9 Light Years from our Solar system Co-ordinates of Right Ascension: 17 44 08.7029 & Declination: -51 50 02.591. The apparent Magnitude of the star is 5.15. The Inner Edge of Habitability Zone is 0.69 AU & the Outer Edge of Habitability Zone: 2.16 AU and the estimated stellar lifespan of the star is 7938 million years. Orbiting around HD 160691 are planet Mu Arae d, Mu Arae b, Mu Arae c.

Mu Arae d the planet is believed to be a hot super earth planet and its existence has been confirmed. The planets appearance is dark sodium haze. The planet is positioned out side of Habitability Zone at Mean Orbital Distance of 0.09 AU and the estimated mass of the planet is 13.992 Earths. The planet Orbits around the star every 9.55 ± 0.03 Days and was discovered by Santos et al in 2004.

Mu Arae b the planet is believed to be a Water Giant, Eccentric planet and its existence has been confirmed. The planets appearance is water giant, eccentric. The planet is at Earthlike Temperatures at Mean Orbital Distance of 1.5 AU and the estimated mass of the planet is 1.67 Jupiters. The planet Orbits around the star every 654.5 Days and was discovered by TINNEY C., BUTLER P., MARCY G., JONES H., PENNY A., VOGT S., APPS K. & HENRY C. on 13 Jun 2002.

Mu Arae c the planet is believed to be a Gas Giant, Eccentric planet and its existence has been confirmed. The planets appearance is White ammonia clouds, brown hydrocarbon stains. The planet is positioned out side of Habitability Zone at Mean Orbital Distance of 4.17 AU and the estimated mass of the planet is 3.1 Jupiters. The planet Orbits around the star every 2986 Days and was discovered by H.R.A.Jones on 13 Jun 2002.