RZ Piscium
The star RZ Piscium, surrounded by huge clouds of dust and gas NASA video

A 30-50 million-year-old star named RZ Piscium in the constellation Pisces has confused scientists for a long time due to its dimming and clouds of gas and dust surrounding it. Now, it has been observed that the clouds are formed of dead planets, which the monster star has consumed over the years.

UCLA's Benjamin Zuckerman and a team of US astronomers have discovered that the star, located 550 light-years away from earth, becomes one-tenth as bright as its normal state for as long as two days periodically. Evidently, this dimming is caused when it devours planets, rather than sustaining them. The "massive blobs of dust" block the star's light while they spiral around it.

"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. 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," said Catherine Pilachowski, study co-author and astronomer at the Indiana University.

The star RZ Piscium is different from other ones as it is forming a circle of space debris around it instead of breaking apart planets which are pulled towards it due to tidal forces. Typically, astronomers expect the clouds of dust around a star to dissipate after a few million years. Instead, the clouds have kept increasing, revolving around it at an approximate distance of 30 trillion miles, as the star produces more energy than the sun at infrared wavelengths. Its luminosity is about eight percent infrared, which can be said about only a few stars that have been studied in the past 40 years.

"I've been studying young stars near Earth for 20 years and I've never seen anything like this one," said Zuckerman, a professor of astronomy. "Most sun-like stars have lost their planet-forming disks within a few million years of their birth. 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."

The study, published in the Astronomical Journal, says that the surface temperature of RZ Piscium is around 9,600 degrees Fahrenheit. Its age was detected by the amount of lithium on its surface as lithium level declines with a star's age, according to Joel Kastner, co-author of the study and director of RIT's Laboratory for Multiwavelength Astrophysics.

Data indicates that the debris strewn around the star is like the destruction left behind after a massive natural disaster. It is possible that the star is taking material from a neighbouring dwarf or giant planet which produces streams of gas and dust. Or perhaps, the companion planet has already been destroyed and the debris are merely its leftover parts.

The research was conducted via the European Space Agency's XMM-Newton satellite and the Shane 3-metre telescope at California's Lick Observatory, along with the 10-metre Keck I telescope from W. M. Keck Observatory in Hawaii. Scientists from UCLA, RIT, Indiana University and UC San Diego participated in the study.

Check out NASA's video on the 'winking star' RZ Piscium: