Antares (Alpha Scorpii)
Antares (Alpha Scorpii) is the brightest star in the constellation Scorpius and the 16th brightest star in the sky. It is a red
supergiant and an irregular variable.
Its name means "rival of Mars" (Ares
and Mars being, respectively, the Greek and Roman gods of war), a reference
to its similar appearance to the Red Planet. In fact, since Antares lies
within a zodiacal constellation, which contains the apparent path of the
Sun and planets, it is commonly mistaken for Mars. With a diameter of 800
million km, it would, if put in place of the Sun, reach about halfway to Jupiter.
|Antares (upper left), Rho Ophiuchi (blue), and Sigma
Scorpii (red). Image: Anglo-Australian Obs./Royal Obs. Edinburgh
|Rho Ophiuchi three-star system is to the upper right,
the 22 Scorpi trinary lies just above Antares (near the center bottom).
The globular cluster M4 is just to the
right of Antares. [Note: this image is rotated 90 degrees anticlockwise
with respect to the upper image]. Credit: Jay Ballauer and Phil Jones
using a Takahashi FSQ 106 mm telescope and a SBIG STL11000 CCD camera
A fierce stellar wind blowing from the
surface of Antares has resulted in a circumstellar gas cloud, which is illuminated
by the light from a hot B-type companion star that, at fifth magnitude,
hides within the supergiant's bright glare (separation 3", magnitude 6.5,
period 900 years). Because it contrasts with the brilliant reddish primary,
Antares B may appear green. The components are a challenge to resolve in
amateur scopes. Some observers report success using either a light blue
or an OIII filter to subdue a portion of Antares' light.
||0.9 to 1.1
||M1.5Iab-b + B2.5V
||3,400 K (primary)
||604 light-years (190 pc)
||R.A. 16h 29m 24.4s,
Dec. -26° 25' 55"
||21 Sco, Cor Scorpii, Kalb al Akrab, Vespertilio,
HR 6134, CD -26°11359, HD 148478, SAO 184415, FK5 616, WDS 16294-2626,
CCDM J16294-2626A/B, HIP 80763
|Antares in science fiction
Uhura sings 'Beyond Antares'
|Like many of the brightest stars in Earth's sky,
Antares figures prominently in science fiction. In the Star
Trek universe, it features in the romantic ballad sung by Lieutenant
Uhura (Nichelle Nichols) in the original series episode "The Conscience
of the King" and again hummed by her in "The Changeling." The latter
performance has the unfortunate effect of persuading the alien probe
known as Nomad (see self-repairing
spacecraft) that she is experiencing a biological malfunction,
as a result of which it wipes her memory clean. Antarean brandy is
a beverage served at a dinner on board the Enterprise in
2268 (TOS episode "In Truth There is No Beauty"), while Antarean cider
shows up in the Voyager episode "Shattered."
Michael McCollum's trilogy beginning with Antares Dawn follows
the exploits of a human colony on the planet Alta after Antares explodes
as a supernova in 2512.
• brightest stars