South Africa’s Bushmen reportedly call Antares, a red supergiant in Scorpius constellation, “The Fire Finishing Star”—because, at certain times of the year, it sets before their camp fires have burned out.

Now, astronomers are convinced, that nuclear fires, burning within the core of Antares, will themselves “finish” soon, making this carmine beauty a prime supernova candidate.

Accordingly, Antares is on Wikipedia’s list of 30 possible supernova progenitors. These are stars, whose physical and chemical indicators, amount to warning signals.

Supernova explosions are humungous blasts that occur when stars more massive than our Sun, burn all their nuclear fuel.Currently, the glow of Antares’ simmering nuclear embers—the radiance of its expansive photosphere—can be seen overhead, slightly to the southwest, in the middle hours of the night.

Antares is easy to observe. It is the brightest star in the bejeweled configuration, which the Polynesian Islanders of the South Pacific envision as the “Fish-hook” of their great god, Maui.

It is, in fact, the 15th most luminous star in the night sky—one of the four brightest stellar objects (along with Spica, Regulus and Aldebaran) lying close to the ecliptic (Earth’s orbital plane).

From Nigeria, Antares is highly accessible, visually. It lies south of the celestial equator, which is an extension into space of the imaginary mid-planet divide, which passes 500 or so km off Nigeria’s coast.

With Mars and Saturn, Antares forms a glistening (but gradually dispersing) triangle, which I described a few weeks ago (“Mars Stops The Show,” May 12th).
“Antares” means “anti-Ares” or “rival of Mars,” at least in Roman lore. But some sources trace the appellation to “Ántara,” a mulatto warrior-hero, in pre-Islamic Arabia.

By whatever name, Antares has pretty much reached the end of its evolutionary rope. Even though it is only 11-to-12 million years old, the star has lived fast and furious, burning its candles at both ends.

Astronomers rack that up to size. According to NASA, Antares is about 850 times the diameter of the Sun, 15 times more massive, and 10,000 times brighter.
In astronomy, the bigger they are the faster they burn—and the more violently they burst, when their nuclear fuel is finished.

Mind you, I’m not referring to chemical fuels, such as the petrol that powers vehicles or the kerosene in your kitchen cooker.All that happens, when these substances burn, is the rearrangement of atoms, to create different kinds of materials. The chemical elements themselves remain unaffected.

By contrast, nucleosynthesis occurs in the core of stars, creating new elements and, at the same time, converting some matter into energy.It is gravity that drives this process. The more mass a star has, the greater its internal gravity and, consequently, the tighter it can squeeze the elements in its core—and the more heat it generates.

Squeezing four hydrogen nuclei together, ultimately causes them to fuse and form helium, during which part of their mass is converted to energy, at an astounding ratio.

When helium “ash” accumulates in the core, the process is repeated and helium is fused into carbon. Heavier and heavier elements are fused, until iron ash builds up in the star’s interior, spelling its doom.

In the interim, hydrogen and helium burn simultaneously, in the layers surrounding the core. This heats the star’s exterior, causing it to expand.The visible outermost layer, the photosphere, is red because it is comparatively cooler—about 3500 K, compared with the interior temperature of 600 million K that is required to fuse helium into carbon.
To be continued.