Rare! New discovery in the universe

"Misty Binary Stars": Two rare star systems discovered in the universe

An international team led by Professor Zhu Wei of the Department of Astronomy at Tsinghua University recently announced the discovery of two rare star systems in the universe. Both systems consist of two central stars orbiting each other, surrounded by a gas and dust disk, and the disk is at a certain angle to the orbit of the central star, presenting a magical effect of "fog around binary stars".

The paper on the discovery of these two new celestial bodies, named Bernhard-1 and Bernhard-2, was recently published online in the international academic journal The Astrophysical Journal Letters.

The rendering of the binary star system produced by the scientific research team. (Provided by the scientific research team)

Protoplanetary disks are dense gas surrounding newly formed stars. It is understood that since binary stars and their protoplanetary disks condense from the same huge rotating nebula, the disk is usually located in the same plane as the orbit of the star, just like the orbits of most planets and satellites in the solar system are located in the same plane. However, there is still a rare type of binary star system in the universe, that is, the protoplanetary disk surrounding the binary star is at a certain angle to the orbital plane of the star.

Zhu Wei introduced that due to this tilt, the protoplanetary disk will swing like a gyroscope, and this movement is called "precession". When "precession" occurs, the protoplanetary disk will move between the earth and the star, orbiting the binary star every few decades, causing the overall brightness of the binary star to change regularly. In addition, due to the shielding effect of the protoplanetary disk, the total brightness of the binary star will also change periodically, producing a unique light curve. The two newly discovered celestial bodies, Bernhard-1 and Bernhard-2, are rare binary star systems of this type.

The research team observed that Bernhard-1 was dimming for 112 days out of every 192 days, while Bernhard-2 was dimming for 20 days out of every 62 days. As seen from Earth, these dimming states indicate that one of the stars in each binary is moving behind the disk. When the stars reappear, the brightness of the system returns to normal.

Zhu Wei said that the two binary star systems are 3,000 to 10,000 light-years away from the Earth. Enthusiasts with telescopes with an aperture of 20 cm or more can see the process of their brightness changes, but unfortunately, existing telescopes cannot distinguish between binary stars and protoplanetary disks.

"The discovery of this rare and peculiar system is of great significance to our understanding of planet formation." Zhu Wei said that since the protoplanetary disk is the birthplace of planets, the emergence of this binary star system will help researchers to conduct more in-depth research on non-coplanar structured celestial bodies and the planetary systems they produce. "We also believe that more such rare celestial bodies will be discovered in the near future."

Source: Xinhua News Agency

Planning: Liu Xinhui, Interview and writing: Wei Mengjia, Yang Menghan, Editing: Lian Changyan