Just over a decade ago, astronomers discovered a large gap between two belts surrounding Vega, suggesting that the nearby star likely hosts multiple stars. exoplanets.

Then, in 2021, other researchers saw what they thought was perhaps a signal of a Neptune Or Jupiter-like a gas giant orbiting extremely close to the star. Surely, they thought, when the ultra-sensitive James Webb Space Telescope launches into spacethey will finally obtain definitive proof of the existence of a planet.

But after pointing Webb at the target and collecting more data from the Hubble Space Telescope, NASA scientists didn’t see what they thought they would find. Latest observations seem to suggest that the 1997 sci-fi film Contactbased on an older book by Carl Sagancould have been right after all: there is nothing around Vega except a whirlwind of debris.

“The Hubble and Webb observations together provide so much more detail that they tell us something completely new about the Vega system that no one knew before,” said George Rieke, one of the researchers based at the University of ‘Arizona, in a press release. statement.

In this artist’s rendering, a disk of gas and dust orbits a young star. Astronomers look for lines carved into the disk, a possible sign of orbiting planets.
Credit: NASA/ESA/STScI/Illustration Leah Hustak

Vega, located in the summer constellation Lyra, is about 25 light years, or 150 trillion miles, from Earth. It is a type A star: young, robust and rotating much faster than the sun. This thing, about 450 million years old, is 40 times brighter than the sun, emitting sizzling blue-white light. Its rapid rotation, spinning completely every 16 hours, makes it a difficult target for scientists who want to track its movement and search for tugs from potential planets.

The new studyto be published in two papers In The Astrophysics Journalwas based on a very detailed study of the 100 billion kilometer wide Vega debris disk facing Earth. In the past, this disk was thought to be a circle of planet-forming material; indeed, in our own solar system the planets emerged from such a disk once centered on the sun, but this disk is now long gone.

“The Vega disc is smooth, ridiculously smooth.”

Astronomers were shocked when Webb and Hubble shows nothing to suggest large planets are busy at work, blow away the dustwhich would be typical in a star system the age of Vega, only about 10 percent of the sun. Usually, these nubile stars are surrounded by a lot of dust, enriched by frequent star collisions. asteroids And comets.

Hubble detects material the size of smoke particles, and Webb can pick up particles as tiny as a grain of sand, according to NASA. However, neither showed signs of the worlds repel and remove dust, a clue that scientists look for when trying to determine whether a star has planets. The discovery of a pancake-shaped disk with no obvious traces of planets forces them to rethink why the Vega system is not what they expected, and it could offer new insights into formation of planetsin general.

Vega, the fifth brightest star in the sky, as seen by Hubble, left, and Webb.
Credit: NASA / ESA / CSA / STScI / S. Wolff / K. Su / A. Gáspár

“This is unlike other circumstellar disks we have examined,” Andras Gáspár, another member of the research team, said in a statement. “The Vega disc is smooth, ridiculously smooth.”

Despite its softness, the disc seems to have a slight subtle gap far from the star, about twice the distance from Neptune to the sun. The researchers say this rules out the possibility of planets until at least the mass of Neptune.

Ironically, Vega is famous for opening astronomers’ eyes to the idea that other stars could host planets and that the material orbiting a star – apparently the building blocks for making planets – could host life.

“Vega continues to be unusual,” Schuyler Wolff, lead author of the study, said in a statement. “The architecture of the Vega system is markedly different from our own solar system, where giant planets like Jupiter and Saturn prevent dust from spreading as it does with Vega.”