In this week’s edition of New Unexplained Astronomical Phenomena, a team of astronomers led by Dr Leigh Smith from Cambridge found a star 100 times larger than our sun that almost disappears from the sky every few decades. They also don’t know why he’s doing it.
The star, called VVV-WIT-08, is located 25,000 light years away, and its luminosity decreases by a factor of 30 instead of completely disappearing. It’s not the first star to be discovered with this changing luminosity pattern, but evidence is starting to accumulate that it could be another example of a new class of stars.
The name of VVV-WIT-08 itself needs an explanation. The “WIT” in the middle actually means “what is it,” what astronomers refer to as stars that are difficult to classify into a particular established category.
The team, which included members of the University of Edinburgh, University of Hertfordshire, University of Warsaw and Andres Bellow University in Chile, found this new variable star using the VISTA variables. in the Via Lactea (VVV) survey, which uses the VISTA telescope in Chile. Its gradation pattern was then confirmed using the optical gravitational lens experiment (LORGNER), which showed the star darkening in both infrared and visible light.
Astronomers believe the most likely cause of this darkening process are opaque disks of dust and gas, or potentially a binary companion or planet transiting past the star. But more original explanations cannot yet be ruled out. With more and more stars being added to this new category of “flashing giants”, it is only a matter of time before more theories proliferate on what could be causing the gradation. And there are still so many phenomena to discover and explanations to explore.
Cambridge – Astronomers spot ‘flashing giant’ near center of Galaxy
Royal Astronomical Society – VVV-WIT-08: the giant star that flashed
Sci-News – A giant “flashing” star spotted in the central region of the Milky Way
Artist’s impression VVV-WIT-08
Credit: Amanda Smith