Astronomers have detected a giant blinking star which is many times bigger than our sun, near the heart of the Milky Way Galaxy. The star known as VVV-WIT-08 is more than 25,000 light-years away from Earth. When scientists detect variable stars that do not fit in any established categories, they call them “what is this” – “WIT” objects.
Observations show that over the time of a few hundred days the huge star’s light dimmed by 97% and then slowly returned to its original brightness.
Scientists noticed the strange dimming star by analyzing data previously gathered by the Vista telescope in Chile. The researchers concluded that this star may belong to a new class of “blinking giant” binary star system. This class includes giant stars which are 100 times larger than the sun and eclipsed every few decades by an unseen companion. This companion could be a planet or even another star.
“It’s amazing that we just observed a dark, large and elongated object pass between us and the distant star and we can only speculate what its origin is…” said Dr. Sergey Koposov from the University of Edinburgh.
VVV-WIT-08’s mystery companion seems to have a large opaque disk, which blocks out much of the star’s light. The astronomers calculations suggested the disc must be gigantic and was tilted to look like an ellipse when viewed from Earth.
“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,” said another researcher from the University of Hertfordshire.
However this is not the first blinking star that astronomers have observed. A large dust disc causes the giant star Epsilon Aurigae to dim around 50% every 27 years. A study of similar star systems including giant stars that dim and brighten, helped researchers determine that a new class of “blinking giant” stars may exist and need to be further investigated.
In the press release lead study author Leigh Smith said: “There are certainly more to be found, but the challenge now is in figuring out what the hidden companions are, and how they came to be surrounded by discs, despite orbiting so far from the giant star”.