Astronomers Discover VVV-WIT-08 Star Flickering in a Cycle Over 25,000 Light-Years Away
An international team of astronomers has observed the VVV-WIT-08 star dimming to the point of nearly disappearing from the sky. While many stars vary in brightness due to being obscured by another star in a binary system, it is quite rare for a star to fade over a period of months and then brighten again.
Simulation of the VVV-WIT-08 star being obscured. (Image: Amanda Smith/Cambridge University).
Researchers believe that VVV-WIT-08 may belong to a newly identified group of giant flickering binary stars, where a massive star, 100 times the size of the Sun, is periodically obscured by an unseen companion. This companion could be another star or a planet surrounded by a dusty disk. This dusty disk causes the giant star to disappear and reappear in the sky.
The research findings were published in the Monthly Notices of the Royal Astronomical Society. The study was led by Dr. Leigh Smith from the Institute of Astronomy at the University of Cambridge, along with scientists from the University of Edinburgh, the University of Hertfordshire, the University of Warsaw in Poland, and Andrés Bello University in Chile.
Given that VVV-WIT-08 is located in a dense star region of the Milky Way, researchers considered whether some dark object might be drifting in front of the star. However, simulation results indicate that a large amount of dark matter would need to drift around the galaxy for this scenario to occur, which is deemed impossible.
Researchers have previously noted a similar star system. Every 27 years, the giant star Epsilon Aurigae is partially obscured by a massive dust disk, dimming by about 50%. A second example is the star TYC 2505-672-1, discovered a few years ago, which fades in a 69-year cycle.
VVV-WIT-08 was discovered by the VISTA Variables in the Via Lactea Survey (VVV) program, using the VISTA telescope in Chile, operated by the European Southern Observatory. Meanwhile, the Optical Gravitational Lensing Experiment (OGLE), run by the University of Warsaw, also monitored the dimming process of the star. OGLE’s regular observations played a crucial role in modeling VVV-WIT-08, showing that the star dims in both visible and infrared light.