Astronomers have discovered a giant “blinking” star towards the center of the Milky Way, more than 25,000 light-years away.
An international team of astronomers has observed a star that is almost disappearing from the sky, with the VVV-WIT-08 reduced in brightness by a factor of 30. The brightness of many stars changes because they pulsate or are covered by another star. Binary systemIt is very rare for a star to darken for several months and then brighten again.
Researchers believe that VVV-WIT-08 may belong to a new class of “blinking giants.” Star system,here Giant star 100 times as large as the Sun, it is eclipsed once every few decades by a companion in an orbit that is not yet visible. A companion star, which may be another star or planet, disappears into the sky and reappears, surrounded by an opaque disk covering a giant star. The study is published in the following journals: Monthly Notification of the Royal Astronomical Society..
This discovery was led by Dr. Lee Smith of the Institute of Astronomy, University of Cambridge, in collaboration with scientists from the University of Edinburgh, Hartfordshire University, the University of Warsaw in Poland, and Andres Bellho University in Chile.
“It’s amazing to just observe a dark, large, elongated object passing between us. Far star And we can only guess its origin, “said co-author Dr. Sergei Koposov of the University of Edinburgh.
Because the stars are located in dense areas of the Milky Way, researchers suspected that an unknown dark object might have just accidentally drifted in front of a giant star. However, simulations have shown that an incredible number of dark bodies need to float around the galaxy for this scenario to happen.
Another star system of this kind has long been known. The giant star Epsilon Aurigae is partially covered by giant discs every 27 years, but only about 50% darkens. The second example, TYC 2505-672-1, was discovered several years ago and holds the current record of the eclipsing variable with the longest orbital period (69 years). candidate.
The UK-based team discovered two more of these strange giants in addition to the VVV-WIT-08. This suggests that these may be a new class of “blinking giants” for astronomers to investigate.
VVV-WIT-08 was discovered by the VISTA variable in the Via Lactea Survey (VVV). The project is run by the European Southern Observatory using the UK-made VISTA telescope in Chile. It took me 10 years to find an example of how the brightness of the infrared part of the spectrum changes.
Professor Philip Lucas of the University of Hertfordshire, co-leader of the project, said: Variable star This does not fit into an established category called “What is this?” Or “WIT” object. I really don’t know how these flashing giants were born. After years of planning and collecting data, we are very pleased to see such discoveries from VVV. “
VVV-WIT-08 was discovered using VVV data, but star dimming was also observed by the Optical Gravitational Lensing Experiment (OGLE), a long-term observation campaign conducted by the University of Warsaw. OGLE makes observations more often, but is closer to the visible part of the spectrum. These frequent observations are the key to modeling the VVV-WIT-08 and have shown that giant stars are dimmed by the same amount in both visible and infrared light.
Currently, there are about six potential known star systems of this type. Performer And a big opaque disc. “There is certainly something to be discovered, but the challenge now is what the hidden companions are and how they are in orbit far from the giants. “It’s about figuring out what you’re surrounded by,” Smith said. “By doing so, you might learn something new about how these types of systems evolve. Hmm.”
Monthly Notification of the Royal Astronomical Society (2021). DOI: 10.1093 / mnras / stab1211
University of Cambridge
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Astronomers discover a “blinking giant” near the center of the galaxy
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