Also known as Alpha Scorpii. A brilliant jewel set within the Milky Way, Antares sits amid the Zodaiacal constellation Scorpius (or Scorpio), the celestial scorpion, one of the few constellations that actually looks like what it represents. The great star, a class M (M1.5) red supergiant gleaming redly at the scorpion's heart, has a color similar to Mars. Antares has the mass of about 15.5 times that of Earth's sun, and is 10,000 times as bright. The lifetime of a red supergiant like Antares is quite short, measurable in tens of thousands of years. Antares may have become a red supergiant as recently as 150 AD.
Antares has a smaller, whitish companion, (known as Antares B). However, in the red light of Antares this companion star appears green.
Prescot mentions that Antares is about 400 light-years from Earth. This seems to be based on the prevalent knowledge about Antares in the early 1970's (which would have been the time that Prescot's first tapes were made). More modern estimates place Antares at a distance of about 600 light-years from Earth.