Astronomers have noticed a giant blinking star, 100 instances the dimensions of the solar, lurking near the heart of the Milky Way.
Telescope observations revealed that over just a few hundred days the big star, which lies greater than 25,000 mild years away, dimmed by 97% after which slowly returned to its former brightness.
The sudden and dramatic darkening was in all probability brought on by an orbiting planet or companion star surrounded by a disc of opaque mud crossing in entrance and blocking out mild that might in any other case have reached Earth.
“It appeared to return out of nowhere,” mentioned Dr Leigh Smith at Cambridge College’s Institute of Astronomy, on the sudden dimming of the star. It started to fade in early 2012 and nearly vanished by April that yr earlier than recovering over the following 100 days.
Astronomers seen the mysterious dimming star in knowledge gathered by the Vista telescope, operated by the European Southern Observatory in Chile. The instrument has been watching a billion stars for practically a decade in search of examples that various in brightness within the infrared realm of the electromagnetic spectrum.
When scientists find variable stars that don’t sit inside established classes, they name them “what is that this” or “WIT” objects. Their newest discovery bears the identify VVV-WIT-08.
As a result of the massive star was in such a dense area of the galaxy, the researchers puzzled whether or not an unknown darkish object might need strayed in entrance of it by probability. Simulations advised this was extremely unlikely with out an implausible quantity of darkish objects floating across the Milky Way.
Way more possible was that the telescope’s view of VVV-WIT-08 was obscured when a dusty disc round an orbiting planet or second star received in the best way. The astronomers’ calculations, reported within the Monthly Notices of the Royal Astronomical Society, advised the disc was tilted to appear to be an ellipse from Earth and needed to be gigantic, having a radius at the least 1 / 4 of the gap from the Earth to the solar.
It’s not the primary blinking star astronomers have found. An enormous mud disc causes the giant star Epsilon Aurigae to dim by about 50% each 27 years. One other star often called TYC 2505-672-1 is a component of a binary system and is eclipsed by the disc round its companion star each 69 years. It’s unclear when VVV-WIT-08 will dim once more, however astronomers consider it’s going to occur within the subsequent 20 to 200 years. Two extra blinking stars have been noticed alongside VVV-WIT-08, however the researchers have fewer particulars on these.
The flurry of discoveries will assist astronomers perceive what appears to be a brand new class of “blinking giant” stars. “When you begin to construct up collections of a number of of this stuff, you possibly can have a look at their properties in combination and unpick the mysteries of the place these discs come from,” mentioned Smith. “It permits us to learn the way these programs evolve and what they do on the finish of their lives.”