Antares (Alpha Scorpii) is the brightest star in the constellation Scorpius and one of the brightest stars in the night-time sky. Along with Aldebaran, Spica, and Regulus it is one of the four brightest stars near the ecliptic. The similarly colored Aldebaran lies almost directly opposite Antares in the Zodiac.

Antares is a class M supergiant star, with a diameter of approximately 1.33 ? 109 km, or if in place of our sun, it would slightly more than encompass the average orbit of Mars, and is approximately 600 light years from earth. Visually, its luminosity is about 10,000 times that of the Sun but overall, taking into account that the star radiates a considerable part of its energy in the infrared part of the spectrum the luminosity equals roughly 65,000 times that of the Sun. The mass of the star is calculated to be 15 to 18 solar masses. Its large size and relatively small mass give Antares a very low density.

Antares has a hot blue companion star (Antares B) at a distance of about 2.9 degrees. Although it is 5th magnitude, it is normally difficult to see because of Antares' glare, but can be observed with a small telescope for a few seconds during lunar occultations while Antares itself is hidden by the Moon; it was discovered during one such occultation on April 13, 1819. The orbital period is 878 years.

In Star Trek, the Antares system is a binary star system, (TOS: "A Piece of the Action") located in the Antares sector. (VOY: "Message in a Bottle") The primary star is called Antares (or Alpha Scorpii). (TOS: "Charlie X"). The Antares system is home to the Antaran species, (ENT: "The Breach") and it is the location of the Antares maelstrom and the source of Antarean brandy (TOS: "Is There in Truth No Beauty?") and Antarean glow water. (TOS: "The Trouble with Tribbles") The Starfleet-operated Beta Antares Ship Yards are also located in this system. (VOY: "Message in a Bottle")

The Antares Ship Yards are located at Antares IV (TOS: "A Piece of the Action"). The USS Antares, a Federation starship, is named after this star system, and there are Antares-class starships and Antares-class freighters.

The Antares maelstrom is some sort of astronomical object in the Antares system - probably some sort of large swirling spatial anomaly. Khan Noonien Singh swore he would chase Admiral James T. Kirk "round the moons of Nibia and round the Antares maelstrom and round perdition's flames" before he gave him up. (Star Trek II: The Wrath of Khan)