They discover a giant star that flickers inside the Milky Way

(CNN) – A giant star blinks near the center of our Milky Way like a stellar beacon, according to new observations from astronomers. The star is more than 25,000 light years from Earth.

Known as VVV-WIT-08, the star dimmed so much that it almost disappeared from view during astronomers’ observations.

It is not uncommon for the brightness factor of a star to change. Some stars pulse, or one star within a stellar pair, called a binary, can be eclipsed by another. But it is incredibly rare for a star to fade and shine again, that is, to flicker.

Observation of this star has led researchers to believe that it may belong to a new class: a “blinking giant” binary star system. This class includes giant stars a hundred times larger than our sun that are dwarfed every few decades by an invisible companion, which could be a planet or another star.

This companion is likely surrounded by a disk of matter that hides the giant star, causing the flicker pattern observed by astronomers.

The study was published Friday in the newsletter. Monthly Notices of the Royal Astronomical Society.

The center of our galaxy is a dense region that includes a supermassive black hole, superclusters of stars, gas streams, and magnetic filaments.

“It is surprising that we have barely observed a large, elongated dark object passing between us and the distant star, and we can only speculate what its origin is,” said Sergey Koposov, co-author of the study and professor of observational astronomy at the University of Edinburgh. , it’s a statement.

At first, the researchers speculated that an unknown dark object could pass in front of the giant star, but this would only be possible if there were a large number of these objects in the galaxy, which is unlikely.

Studying other unique star systems, such as giant stars darkening and brightening, or displaying this flicker pattern, helped researchers determine that there might be a new class of blinking giant stars that need to be investigated. So far, there appear to be about six such systems.

The star system in this study was found using the “VISTA Variables in the Via Lactea” survey, or VVV. This project, which uses the VISTA telescope of the European Southern Observatory in Chile, has observed a billion stars for almost a decade to see how their brightness varies.

“Every now and then we find variable stars that don’t fit into any established category, which we call ‘what-is-this’ objects, or ‘WITs,'” explained Philip Lucas, VISTA project leader and professor at the University of Hertfordshire , it’s a statement. ‘We really don’t know how these blinking giants came to be. It’s exciting to see these VVV discoveries after so many years of planning and data collection.

The star’s dimming was also observed by the Optical Gravitational Lens Experiment, known as OGLE, a study of the sky led by the University of Warsaw. The data sets from both studies showed that the star darkened equally in infrared and visible light.

Astronomers will continue to search for more blinking giant star systems to learn more about them.

“There is certainly more to find, but the challenge now is to find out what the hidden companions are and how they came to be surrounded by disks, despite orbiting so far from the giant star,” said Leigh Smith, lead of the discovery and research associate. at the Institute of Astronomy at the University of Cambridge, in a statement. “By doing so, we could learn something new about how these types of systems evolve.”