An unpredictable blinking star appears to be a planet eater

From dark matter to UFOs, outer space is full of mysteries. One such mystery has surrounded RZ Piscium, a star that’s been acting pretty weird by dimming unpredictably. Astronomers said it appeared to be winking. But a new study made have cracked the code and, as it turns out, RZ Piscium’s winks aren’t come-ons. They’re more likely signs the star has been eating planets for lunch.

“Our observations show there are massive blobs of dust and gas that occasionally block the star’s light and are probably spiraling into it,” said Kristina Punzi, a doctoral student at the Rochester Institute of Technology who worked on the research. “Although there could be other explanations, we suggest this material may have been produced by the break-up of massive orbiting bodies near the star.”

As astronomers have observed the blinking star over the years, they’ve recorded its strange behavior but have struggled for a sure explanation.

In the new study, Punzi and her colleagues suggest that RZ Piscium is surrounded by dense pockets of gas and dust, which dim the star’s light as they orbit it. The astronomers think these blobs of matter might be remnants of rocks that have collided while orbiting the young star, in a chain of reactions that has leveled them to dust. Were the star young, these clouds may be expected to coalesce into planets.

But this explanation wasn’t conclusive. In fact, another explanation suggested the star is actually older than our own and has been devouring its planets as it matures into a red giant. In other words, the dust clouds are table scraps from dead planets.

After analyzing RZ Piscium’s X-ray output and lithium makeup (both higher in younger stars) Punzi and her colleagues determined it’s around 30 million to 50 million years old. That’s relatively young. But other measurements suggest the star is also too old to be orbited by so much gas and dust, unless that matter is the remnants of dead planets. So the researchers settled somewhere in between.

“Most sun-like stars have lost their planet-forming disks within a few million years of their birth,” said Ben Zuckerman, an astronomy professor at the University of California, Los Angeles. “The fact that RZ Piscium hosts so much gas and dust after tens of millions of years means it’s probably destroying, rather than building, planets.”

A paper detailing the research was published in the Astronomical Journal.