2021-06-11

Astronomers have discovered a strange “shimmering giant star” near the center of the Milky Way

By yqqlm yqqlm

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Astronomers have discovered a strange “shimmering giant star” near the center of the Milky Way

Researchers believe that VVV-WIT-08 may belong to a new type of “blinking giant” binary star system. One of the giant stars-100 times larger than the Sun-is obscured by a companion star in an unseen orbit every few decades. This companion star, possibly another star or planet, is surrounded by an opaque disk that covers the giant star, causing it to disappear and reappear in the sky. The research was published in the Monthly Bulletin of the Royal Astronomical Society.

This discovery was led by Dr. Leigh Smith of the Institute of Astronomy at the University of Cambridge, in collaboration with scientists from the University of Edinburgh, the University of Hertford, the University of Warsaw in Poland, and the University of Andres Bello in Chile.

Sergey Koposov, a research co-author from the University of Edinburgh, said: “It’s surprising that we have just observed a dark, huge, elongated object passing between us and a distant star. , We can only guess what its origin is.”

Because this star is located in a dense area of ​​the Milky Way, the researchers considered whether some unknown dark objects might just accidentally drift to this huge In front of the stars. However, the simulation results show that there must be a large number of dark celestial bodies floating around the Milky Way before this can happen.

Researchers already knew about another similar star system. The superstar Epsilon Aurigae is partially obscured by a huge dust disk every 27 years, but only dimmed by about 50%. The second example is TYC 2505-672-1, discovered a few years ago. It holds the current record of the longest eclipse binary system with the longest orbital period-69 years-VVV-WIT-08 is currently a contender for this record. .

In addition to VVV-WIT-08, the team in the United Kingdom also discovered two other such peculiar giant stars, indicating that these may be a new type of “shimmering giant stars” that astronomers want to study. “.

VVV-WIT-08 was discovered by the VISTA Variables in the Via Lactea (VISTA Variables in the Via Lactea, or VVV for short) project. This project uses the British VISTA telescope built in Chile and is operated by the European Southern Observatory. The same 1 billion stars have been observed for the past ten years to find examples of different brightness in the infrared part of the spectrum.

The co-leader of the project, Professor Philip Lucas from the University of Hertfordshire, said: “Occasionally, we find variable stars that are not suitable for any given category. We call this’what is this’, or’WIT ‘Celestial bodies. We really don’t know how these twinkling giants are formed. After so many years of planning and collecting data, it is really exciting to see this discovery of VVV.”

Although VVV-WIT -08 was discovered using VVV data, but the dimming of this star was also observed by the Optical Gravitational Lensing Experiment (OGLE), a long-term observation activity run by the University of Warsaw. OGLE makes more frequent observations, but closer to the visible part of the spectrum. These frequent observations are the key to modeling VVV-WIT-08, and they show that the giant star is dimmed by the same amount under both visible and infrared light.

It now appears that there are about six potentially known star systems of this type. Smith said: “There will definitely be more star systems to be discovered, but the challenge now is to figure out what the hidden companion stars are and how they are surrounded by the disk, even though their orbits are so far away from the giant star. In the process, we may learn some new knowledge about how this type of system evolves.”