When astronomers peer into the depths of the Milky Way galaxy, which is our home, they can see a lot of stuff going on. There are endless stars swirling masses of gas and other features, but one light source, in particular, has caught the attention of researchers that are trying to understand exactly what it is. It’s a star… but it’s “blinking.” The object is called VVV-WIT-08, and it might belong to an entirely new class of giant stars called a “blinking giant.” That is if scientists can figure out what is making it appear to blink.
Observing the star isn’t easy, as it’s roughly 25,000 light-years away and is positioned between Earth and the galactic center. The center of the Milky Way, as is the case with most galaxies, is densely packed with stars, so spotting individual stars and observing how they behave can be challenging. In the case of VVV-WIT-08, observations took months due to the star’s exceedingly strange habit of growing dimmer and dimmer for a long period of time and then returning to full brightness.
When astronomers search for exoplanets, one of the primary tools in their arsenal is their ability to use high-powered telescopes to observe changes in the brightness of distant stars. If a star grows slightly dimmer for a short period of time before brightening again, that’s a good sign that there’s a planet orbiting it. When that planet passes between the star and Earth, we can’t see the planet itself but we can see the reduced brightness, and that can tell us a lot about the object that passed in front of it.
Researchers believe VVV-WIT-08 is also being orbited by something that is blocking out its light, but they have absolutely no idea what it is. The star itself is massive, roughly 100 times larger than our own Sun, and it “blinks” every few decades. And when the star grows dimmer in the sky, it is a dramatic change. Whatever is orbiting the star nearly blocks out all of its light, and that means it must be huge. It’s a huge mystery, and even the name of the star hints at the fact that astronomers can’t explain it.
“Occasionally we find variable stars that don’t fit into any established category, which we call ‘what-is-this?’, or ‘WIT’ objects,” Professor Philip Lucas, co-leader of the project, said in a statement. “We really don’t know how these blinking giants came to be. It’s exciting to see such discoveries from VVV after so many years planning and gathering the data.”
The search is already on for similar star systems. The more examples of these “blinking giants” that scientists can spot, the better the chances of being able to explain why they look the way they do.