Astronomers explain the strange change in the brightness of a distant star

(ORDO NEWS) — The star Gaia17bpp slowly changes brightness, dimming and flaring up again over several years.

This strange behavior may be due to the presence of its neighbor, a small star surrounded by a vast cloud of dust.

The Gaia Space Observatory conducts astrometric observations, tracking the positions and luminosities of billions of distant stars with high precision.

One of them, Gaia17bpp, attracted the attention of scientists with unusual behavior: over the course of several years, it gradually becomes brighter.

This feature of Gaia17bpp was explained by Anastasios Tzanidakis and James Davenport.

They presented their findings at the 241st meeting of the American Astronomical Society (AAS), which is taking place these days.

Briefly about the work is described in a press release from the University of Washington.

To better follow the behavior of Gaia17bpp, the scientists used not only Gaia data, but also earlier observations made with the Pan-STARRS1, WISE/NEOWISE and ZTF telescopes.

The work showed that between 2010 and 2012 the star strongly lost its luminosity, then remained dark for seven years, and after 2019 it began to sharply gain brightness.

Astronomers have never seen anything like it before. Then Tzanidakis and Davenport turned to even earlier archival data, up to the observations of the 1950s.

It turned out that during this period Gaia17bpp practically did not change.

Astronomers explain the strange change in the brightness of a distant star 2
Gaia17bpp on telescope images

This made it possible to associate the strange behavior of the star not with its features, but with the presence of an unusual neighbor.

“We believe that Gaia17bpp is part of an extremely rare type of binary system that includes the star itself, large and old, as well as a smaller partner surrounded by a vast disk of dust,” Tzanidakis said.

“Our analysis showed that the two stars rotate very slowly, making a complete revolution around each other in a thousand years.”

Only a few such binaries are known so far, scientists say, including Epsilon Aurigae, which is eclipsed every 27 years by a partner carrying a vast, opaque disk of dust.

However, the nature of such systems remains a matter of controversy. Their strange behavior may well find other explanations, as suggested, for example, for an eclipsing star in the constellation Leo Minor.

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