Astronomers have spotted a giant blinking star, 100 times the size of the sun, lurking near the heart of the Milky Way .
Telescope observations revealed that within a few hundred days, the enormous star, which is over 25,000 light years away, dimmed by 97%, then slowly returned to its old brightness.
The oUnexpected and dramatic darkening was likely caused by an orbiting planet or companion star surrounded by an opaque dust disk passing through and blocking light that would otherwise have reached Earth.
" She seemed to come out of nowhere, "said Dr. Leigh Smith of the Institute of Astronomy , on the Sudden darkening of the star. It started to fade in early 2012 and was almost gone by April of that year before recovering over the next 100 days.
Astronomers have noticed the mysterious obscured star in data collected by the Vista Telescope, operated by the European Southern Observatory in Chile. The instrument has observed a billion stars for nearly a decade, looking for examples of varying luminosity in the infrared region of the electromagnetic spectrum.
When scientistsfiques discover variable stars which are not part of the established categories, they call them "what is" or "WIT" objects. Their latest discovery is named VVV-WIT-08.
Because the huge star was in such a dense region of the galaxy, the researchers found themselves are asked if an unknown dark object may have strayed in front of it by chance. Simulations suggested that this was highly unlikely without an implausible number of dark objects floating around the Milky Way.
Much more likely was than the telescope view of VVV-WIT-08 was obscured when a dusty disk around an orbiting planet or a second star interfered. The calculations of the astronomers, reported in the Monthly notices from the Royal Astronomical Society , suggested that the disc was tilted to resemble an ellipse of the Earth and should be gigantic, having a radius of at least a quarter of the distance from Earth to the sun.
This is not the first blinking star discovered by the astronomers. Huge disk of dust causes giant star Epsilon Aurigae to decrease by about 50% every 27 years. Another star known as TYC 2505-672-1 is part of of a binary system and is eclipsed by the disk around its companion star every 69 years. It is not known when VVV-WIT-08 will decline again, but astronomers believe it will happen in the next 20 to 200. Two other flashing stars were spotted next to VVV-WIT-08, but theresearchers have fewer details on these.
The wave of discoveries will help astronomers understand what appears to be a new class of "flashing giant" stars . "Once you start building collections of several of these items, you can examine their properties as a whole and unravel the mysteries of the origin of these records," Smith said. "It allows us to learn how these systems evolve and what they do at the end of their life. "