Distinctly reddish when viewed with the naked eye, Antares is a slow irregular variable star that ranges in brightness from an apparent visual magnitude of +0.6 down to +1.6.

It is located about 170 parsecs (550 ly) from Earth at the rim of the Upper Scorpius subgroup, and is illuminating the Rho Ophiuchi cloud complex in its foreground.

Its traditional name Antares derives from the Ancient Greek Ἀντάρης, meaning "rival to Ares", due to the similarity of its reddish hue to the appearance of the planet Mars.

[16] Its traditional name Antares derives from the Ancient Greek Ἀντάρης,[17] meaning "rival to Ares", due to the similarity of its reddish hue to the appearance of the planet Mars.

[19] Some scholars have speculated that the star may have been named after Antar, or Antarah ibn Shaddad, the Arab warrior-hero celebrated in the pre-Islamic poems Mu'allaqat.

For two to three weeks on either side of November 30, Antares is not visible in the night sky from mid-northern latitudes, because it is near conjunction with the Sun.

Radial velocity variations were observed in the spectrum of Antares in the early 20th century,[24] and attempts were made to derive spectroscopic orbits.

[26] Antares was first reported to have a companion star by Johann Tobias Bürg during an occultation on April 13, 1819,[27] although this was not widely accepted and dismissed as a possible atmospheric effect.

[4] Research published in 2018 demonstrated that Ngarrindjeri Aboriginal people from South Australia observed the variability of Antares and incorporated it into their oral traditions as Waiyungari (meaning 'red man').

It is a member of the Upper Scorpius subgroup of the association, which contains thousands of stars with a mean age of 11 million years.

Antares is located about 170 parsecs (550 ly) from Earth at the rim of the Upper Scorpius subgroup, and is illuminating the Rho Ophiuchi cloud complex in its foreground.

Spectroscopic examination of the energy states in the outflow of matter from the companion star suggests that the latter is over 220 AU beyond the primary (about 33 billion km).

[6] Due to the nature of the star, the derived parallax measurements have large errors, so that the true distance of Antares is approximately 550 light-years (170 parsecs) from the Sun.

[53] Like most cool supergiants, Antares's size has much uncertainty due to the tenuous and translucent nature of the extended outer regions of the star.

Defining an effective temperature is difficult due to spectral lines being generated at different depths in the atmosphere, and linear measurements produce different results depending on the wavelength observed.

[56] Interferometry allows synthesis of a view of the stellar disc, which is then represented as a limb-darkened disk surrounded by an extended atmosphere.

[57][58] Antares is now known to be somewhat larger;[59] for instance, the Hipparcos satellite's trigonometric parallax of 5.89±1.00 mas[60] with modern angular diameter estimates lead to a radius of about 680 R☉.

[11] Older radii estimates exceeding 850 R☉ were derived from older measurements of the diameter,[55] but those measurements are likely to have been affected by asymmetry of the atmosphere and the narrow range of infrared wavelengths observed; Antares has an extended shell which radiates strongly at those particular wavelengths.

Antares, like the similarly sized red supergiant Betelgeuse in the constellation Orion, will almost certainly explode as a supernova,[61] probably in 1.0 to 1.4 million years.

[13] As it falls short of the mass limit required for stars to undergo a supernova, it will likely expand into a red giant before dying as a massive white dwarf similar to Sirius B.

In MUL.APIN, which dates between 1100 and 700 BC, it is one of the stars of Ea in the southern sky and denotes the breast of the Scorpion goddess Ishhara.

[15] In ancient Egypt, Antares represented the scorpion goddess Serket (and was the symbol of Isis in the pyramidal ceremonies).

The Māori people of New Zealand call Antares Rēhua, and regard it as the chief of all the stars especially the Matariki.

[68] The Wotjobaluk Koori people of Victoria, Australia, knew Antares as Djuit, son of Marpean-kurrk (Arcturus); the stars on each side represented his wives.