Difference between revisions of "Antares"
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Antares, also known as Alpha Scorpii is a binary system that consists of a red supergiant and it’s hot, blue companion star located in the constellation [[Scorpius]]. Antares is easily seen in the night sky as the fifteenth brightest star in the sky, known since ancient times. | Antares, also known as Alpha Scorpii is a binary system that consists of a red supergiant and it’s hot, blue companion star located in the constellation [[Scorpius]]. Antares is easily seen in the night sky as the fifteenth brightest star in the sky, known since ancient times. | ||
Revision as of 14:19, June 24, 2009
Antares, also known as Alpha Scorpii is a binary system that consists of a red supergiant and it’s hot, blue companion star located in the constellation Scorpius. Antares is easily seen in the night sky as the fifteenth brightest star in the sky, known since ancient times.
Antares in history
The name Antares is a derivative of the Ancient Greek Αντάρης, meaning "(holds) against Ares (Mars)" because like Mars, the star appears with a reddish hue in the sky. It is this distinct color that made Antares well known to ancient cultures.
In Ancient Egypt, many temples are aligned in such a way that the light from Antares plays a role in the temple ceremonies. The Persians referred to Antares as Satevis and it was referenced in their culture to as far back as 3000 B.C. as one of the four royal stars. In ancient India the star was called Jyeshtha, and the Arabs called it Ķalb al Άķrab, or the "Scorpion's heart"[1].
The star
The Antares system is actually a binary star system even though the unaided eye sees only the primary star. The system itself is estimated to be some 600 light years from Earth; despite this distance Antares still has an apparent luminosity of +0.9 to +1.8, as it is a variable star.
The primary, Antares, is a class M1.5Iab-b supergiant[2] with a radius of 34 AUs, or some 700 times the radius of our own sun, if the star was at the center of our solar system, it would extend to between the orbits of Mars and Jupiter. Despite Antares’ size, it contains only 15 to 18 times the mass of the sun; giving Antares a very low average density. Its visual luminosity is some 10,000 time that of the sun, with an absolute luminosity of 60,000 times, much of which is in the infrared. Like all M class stars, its surface is relativity cool in comparison to other stars, at 3600K[3].
Antares b, the companion star, is a blue star of spectral type B2.5V. Although much dimmer then it’s giant companion, Antares b is still 170 times as luminous as our sun. By itself the star could be seen by the unaided eye, but because of the glare of its neighbor a small telescope is required to see the star at all. It is estimated that the two stars are some 550AUs from each other, but their orbit is still poorly understood.
Antares is coming towards the end of its stellar evolution and will soon develop an iron core, the last stage for a star of its mass before exploding into a supernova[3].
References
- ↑ Richard Hinckley Allen, Star-names and their meanings (1936), p. 365.
- ↑ http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=antares&submit=SIMBAD+search
- ↑ 3.0 3.1 http://www.astro.illinois.edu/~jkaler/sow/antares.html
