London, June 11
An international team of astronomers has spotted a giant star “blinking” towards the center of the Milky Way, more than 25,000 light years away.
The star, VVV-WIT-08, dimmed by a factor of 30, so that it almost disappeared from the sky. While many stars change in brightness because they pulsate or are eclipsed by another star in a binary system, it is exceptionally rare for a star to weaken over a period of several months and then light up again, the team said.
Researchers believe VVV-WIT-08 may belong to a new class of “flashing giant” binary star system, where a giant star 100 times larger than the Sun is eclipsed once every few decades by yet another orbital companion. invisible.
The companion, which can be another star or a planet, is surrounded by an opaque disc, which covers the giant star, causing it to disappear and reappear in the sky. The study is published in the Monthly Notices of the Royal Astronomical Society.
“It is amazing that we have just observed a dark, tall and elongated object pass between us and the distant star and we can only speculate on its origin,” said Sergey Koposov of the University of Edinburgh.
Given that the star is located in a dense region of the Milky Way, the researchers wondered if an unknown dark object could have simply drifted past the giant star by chance. However, simulations have shown that there would have to be an implausible number of dark bodies floating around the galaxy for this scenario to be likely.
Another such star system has been known for a long time. The giant star Epsilon Aurigae is partly eclipsed by a huge disk of dust every 27 years, but only darkens by about 50%. A second example, TYC 2505-672-1, was found a few years ago and holds the current record for the eclipse binary star system with the longest orbital period – 69 years – a record for which VVV-WIT -08 is currently a competitor.
The UK-based team also found two more of these particular giant stars in addition to VVV-WIT-08, suggesting that it could be a new class of “flashing giant” stars that astronomers must study.
There now appear to be about half a dozen potential known star systems of this type, containing giant stars and large opaque disks. IANS