The star who closed his factory

There is, in the Taurus Constellation, astar named TYC 8241 2652. It is located 450 light-years from Earth and is barely ten million years old. Until recently it was just an ordinary star, a young analog of our Sun seemingly in the midst of planet formation. But suddenly the star did something unheard of: he turned off the lights and closed the “factory”. Su warm dusty disk of cosmic debris, perfectly visible for two decades,disappeared two and a half years ago, as confirmed by infrared images from the Gemini Sur Observatory, in Chile.

“It’s like taking a conventional photo of the planet Saturn today and then coming back in a couple of years to find that its rings have faded,” explains Ben Zuckerman of the University of California Los Angeles, co-author of the study published today inNature. “We really don’t have a satisfactory explanation for understanding what happened around this star,” adds research leader Carl Melis of the University of California, San Diego. “The disappearing act appears to be independent of the star itself, as there is no evidence to suggest that the star swallowed planetary dust with some mega-flame or some other violent event.”

According to Zuckerman, the disappearance of the dust around TYC 8241 2652 was so rare and so rapid that, initially, he thought his observations were simply in error somewhere. The absence of an existing model for what is happening around this star is forcing astronomers to rethinkwhat actually happens with young solar systems in the process of formation.

“Although we have identified a couple of mechanisms that are potentially viable, none are totally convincing,” Melis added. In one case, the gas produced in the impact that released the dust contributes to rapidly dragging the dust particles towards the star and thus towards the disappearance of the dust disk. The other possibility is that collisions of large rocks that were left from a large original impact caused a new fall of dust particles towards the disk, which would instigate an escape process from the smallest particles to the largest ones.

Vast regions of dust, such as the asteroid belt and another located beyond the orbit of Neptune, are already known in our own solar system. Nearly 30 years ago, NASA’s Infrared Astronomical Satellite (IRAS) was the first to discover similar regions orbiting other stars. Now it is known thathundreds of sun-like stars emit excess infrared radiation that is usually attributed to dusty material orbiting the star, in what are known as scrap rings. This material is believed to be what remains of the formation of a planetary system. But nothing has ever been seen like the disc of dust that disappeared from TYC 8241 2652. A magician of cosmic illusionism.

Angela Posada-Swafford