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astronomers found ‘Blinking giant’ near the center of the galaxy



astronomers found  'Blinking giant' near the center of the galaxy

Astronomers find gigantic ‘flashing’ star at the center of the Milky Way. More than 25,000 light-years away, an international team of astronomers has observed the star VVV-WIT-08, whose brightness has decreased by 30 times, causing it to almost disappear from the sky. While many stars change their brightness because they are pulsating or are obscured by other stars in the binary system, they are pulsating. It is extremely rare for a star to fade over several months and then brighten again. Credit: Amanda Smith, University of Cambridge.

Astronomers find gigantic ‘flashing’ star at the center of the Milky Way. which is more than 25,000 light years away.

An international team of astronomers has observed the star VVV-WIT-08, whose brightness has decreased by 30 times, causing it to almost disappear from the sky. While many stars change their brightness because they pulsate or are obscured by other stars in a binary star system It is extremely rare for a star to fade over several months and then brighten again.

Researchers believe that VVV-WIT-08 may be in the binary constellation. A new class of “blinking giants,” in which giant stars 100 times larger than the Sun are obscured every few decades by their unseen orbital companions. A companion, possibly another star or another planet, is surrounded by an opaque disk covering the giant star, causing it to disappear and reappear in the sky. The study was published in Monthly announcement of the Royal Astronomical Society.

The discovery was led by Dr. Leigh Smith of the Cambridge Institute of Astrophysics by working with scientists at the University of Edinburgh University of Hertfordshire Warsaw University in Poland and the University of Andres Bello in Chile.







Credits: Leigh Smith, Sergey Koposov.

Co-author Dr Sergey Koposov from the University of Edinburgh said: “Surprisingly, we recently observed a large, elongated dark object passing between us and a distant star. And we can guess what its origins are.”

Because stars are located in dense regions of the Milky Way. Researchers have determined whether some unknown dark objects might accidentally drift in front of the giant stars. However, simulations show that there must be an incredible number of dark objects floating around the galaxy for the galaxies. this situation

Other stellar systems of this nature have long been known. Epsilon Aurigae This giant is obscured by enormous dust every 27 years, but dims only by 50%. Second example, TYC 2505. -672-1 was discovered a few years ago. And it holds the current record for an obscure binary star system with the longest orbital period—69 years—recorded by current competitor VVV-WIT-08.

The UK-based team also found two more peculiar giants in addition to VVV-WIT-08, indicating that they may be stars. A new type of “blinking giant” that astronomers must investigate.







Credits: Leigh Smith, Sergey Koposov.

VVV-WIT-08 was discovered by VISTA Variables in the Via Lactea (VVV) survey, a project based on the British-built VISTA telescope in Chile and operated by the European Southern Observatory, which has observed one billion of the same stars. almost decades to find samples with different brightness in the infrared portion of the spectrum.

Professor Philip Lucas, co-head of the project at the University of Hertfordshire, said: “Sometimes we find variable stars that don’t fit into a given category. which we call ‘What is this?’ or ‘WIT’. We really don’t know how these twinkling giants came to be. It is exciting to see such a discovery from VVV after years of planning and collecting data.”

While VVV-WIT-08 was discovered using VVV data, the star’s dimming was observed in the Optical Gravitational Lens Experiment (OGLE), a long-running observation campaign by the University of Warsaw. OGLE made the observations. more often but closer to the visible part of the spectrum. These frequent observations were key for modeling VVV-WIT-08 and found that giant stars dim by the same amount in both visible and infrared light.

Currently, there appear to be about half a dozen known stellar systems of this type. It consists of giant stars and large opaque discs. “There is still a lot to be found. But the challenge now is to find out what the hidden companion is. And why are they surrounded by discs? even orbiting very large stars,” Smith said. We may learn something new about the evolution of this type of system.”


Fiery stars in the universe: rare insights into the evolution of stars.


More information:
Monthly announcement of the Royal Astronomical Society (2021). doi: 10.1093 / min / stab 1211

Provided by the University of Cambridge



reference: Astronomers found ‘Blink Giant’ near the Galaxy’s Center (2021, 11 Jun). Retrieved 11 June 2021 from https://phys.org/news/2021-06-astronomers-giant-center-galaxy. html

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