Antlia

When Nicolas Louis de Lacaille journeyed to the Cape of Good Hope in the 18th century, he mapped about 10,000 stars that weren’t visible in European skies. He used some of those stars to create 14 constellations. All but one of them were named for the rage of the day: science.

One of those is Antlia, the air pump. It was named for a device that created a vacuum for scientific experiments.

Antlia passes low across the south this month as viewed from the southern half of the U.S. It’s not much to look at, though. You need pretty dark skies to see even its brightest star.

That’s not to say there’s nothing interesting in the constellation. Among its treasures is a star named S Antliae, about 260 light-years away. It’s actually a pair of stars. But the pair should merge to form a single star.

S Antliae is a contact binary. That means the two stars are so close together that they’re touching each other. In fact, they’re sharing an outer layer of gas.

The main star in the pair is about twice the mass of its companion. It’s wider than its companion as well, so it’s probably contributing most of the shared gas. Over time, it may transfer enough gas to make the companion the heavier star. After that, the process may reverse, with the companion giving gas back.

That exchange is drawing the stars closer together. Eventually, they’ll merge, perhaps with a short but bright display of fireworks — adding a spark to an unremarkable constellation.
 

Script by Damond Benningfield