Like the dragon Nidhogg in Norse mythology, or the Marvel deity Galactus himself, it turns out our universe has a world eater in it. Okay, that’s a bit dramatic. But astronomers have found that RZ Piscium, a star in the constellation Pisces, has a tendency to crush planets in its orbit into large clouds of gas and dust.
The study, titled “Is the Young Star RZ Piscium Consuming Its Own (Planetary) Offspring?” (see? The scientists are just as dramatic as me) was published in the The Astronomical Journal, sheds light on a short but volatile period in the history of many star systems, including our own.
“We know it’s not uncommon for planets to migrate inward in young solar systems since we’ve found so many solar systems with ‘hot Jupiters’ — gaseous planets similar in size to Jupiter but orbiting very close to their stars,” said Pilachowski, who is the Daniel Kirkwood Chair in the IU Bloomington College of Arts and Sciences’ Department of Astronomy.
“This is a very interesting phase in the evolution of planetary systems, and we’re lucky to catch a solar system in the middle of the process since it happens so quickly compared to the lifetimes of stars.”
Even star systems whose planets are not lost to their sun are unstable in their early history, since newly born planets interact strongly with one another — as well as their sun — through gravity, she added.
Planets that fly too close to their sun — only to be torn apart by its tidal forces — are officially known as “disrupted planets.” With RZ Piscium, the matter near the sun-like star is being slowly ripped apart to create a small circle of debris about the same distance from the star as Mercury’s orbit is from our own sun.
In our solar system, for instance, astronomers have theorised that Uranus and Neptune swapped orbits about 4 billion years ago. But erratic orbits tend to stabilise over time, and fall into regular patterns.
The study’s authors also found the star’s temperature to be about 9,600 degrees Fahrenheit (5,330 degrees Celsius) – only slightly cooler than our sun’s. Another sign of the star’s relative youth: It produces X-rays at a rate roughly 1,000 times greater than our sun.
“This discovery really gives us a rare and beautiful glimpse into what happens to many newly formed planets that don’t survive the early dynamical chaos of young solar systems. It helps us understand why some young solar systems survive – and some don’t,” Pilachowski said.