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Alpha Scorpii, 21 Scorpii

Proper NameAntares
Bayer DesignationAlpha Scorpii
Flamsteed Number21 Scorpii
HR (BSC)6134
Right Ascension16h 29m 24s
Declination-26° 25' 55"
Distance554 light years
170 parsecs
MagnitudeApparent: +1.1
Absolute: -0.8
Spectral ClassM0.5I Red Supergiant
Optimum VisibilityJune
NotesAn immense and brilliant red supergiant, some nine hundred times the diameter of the Sun, Antares is approaching the end of its life and is expected to erupt as a supernova at some time within the next million years.

Truly a giant, Antares, the brightest star in the constellation of Scorpius, has an estimated diameter of 400 million kilometres.

The red light of Antares shines through clouds of dust and gas extending southward from the extensive Rho Ophiuchi Cloud Complex. This particular part of the complex, for obvious reasons, is given the common name of the Antares Nebula, and is also sometimes known as the Cloud Nebula. Imagery provided by Aladin sky atlas

Location of Antares

Antares lies at the heart of Scorpius, the constellation of the Scorpion. Nearby in the sky is M4, a Globular Cluster that is actually ten times farther away than its bright neighbour.

Illustration of a Red Giant

A giant among giants: With an estimated diameter of 400 million kilometres, the red star Antares is large enough to consume the solar system almost to the orbit of Mars.


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