Vampire Star

StarDate

There’s no fountain of youth to make people look younger. But there is one for stars. It’s a process that sounds like something from a horror movie – “stealing” life from another star.

A good example is in Fornax, the furnace, which is low in the south at nightfall. The constellation has only one moderately bright star, Alpha Fornacis. It’s 46 light-years away.

To the eye alone, it’s not much to look at. But binoculars reveal two stars. One of them is bigger and heavier than the Sun. Because of its greater mass, it’s nearing the end of its life, even though it’s almost two billion years younger than the Sun.

The other visible star is smaller than the Sun, and its surface is cooler, so it glows orange. Yet it should be even redder than it is. And that’s where the story of rejuvenation comes in.

The star is a blue straggler. That means its color has shifted to bluer wavelengths. That might be because it merged with another star. The merger would rev up the nuclear reactions in its core, making it hotter and bluer. On the other hand, it might have changed color by simply stealing gas from a third star in the system.

This extra star was discovered in 2016. It’s a white dwarf – a stellar corpse. It’s about half as massive as the Sun, and it’s quite close to the blue straggler. So the straggler might have siphoned away the star’s life – taking some of its gas to “rejuvenate” its own appearance.

Script by Damond Benningfield