Webb telescope discovers that the hot young star Vega is actually quite lonely

Just over a decade ago, astronomers discovered a large gap between two belts orbiting Vega, indicating that the nearby star is likely home to several stars. exoplanets.

Then in 2021, other researchers saw what they thought might be a signal of one Neptune or Jupiter-like gas giant that orbits extremely close to the star. Sure, they thought, when they were ultra-sensitive James Webb Space Telescope launches in roomthey will finally get definitive proof of a planet.

But after pointing Webb at the target and collecting more data from the Hubble Space Telescope, NASA Scientists haven’t seen what they thought they would find. The latest observations seem to suggest that the 1997 science fiction film Contactbased on an older book by Carl SaganHe might have been right after all – that there is nothing but a swirl of rubble around Vega.

“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,” George Rieke, one of the researchers at the University of Arizona, said in an interview. statement.

In this artistic rendering, a disk of gas and dust moves around a young star. Astronomers look for lanes carved into the disk, a possible sign of orbiting planets.
Credit: NASA/ESA/STScI/Leah Hustak illustration

Located in the summer constellation Lyra, Vega is about 25 light-years, or 150 trillion miles, from Earth. It is an A-type star: young, robust and rotating much faster than the Sun. This thing, about 450 million years old, is 40 times brighter than the sun and emits blistering blue-white light. Its rapid rotation, complete one complete turn every 16 hours, makes it a challenging target for scientists who want to track its motion and look for tugs of potential planets.

The new one studyto be published as two paper in The Astrophysical Journalwas based on a very detailed look at Vega’s 100 billion-mile-wide debris disk, which is pointed toward Earth. In the past, this disk was thought to be a circle of planet-forming material; In our own solar system, planets emerged from such a disk that was once at the center of the sun, but now that disk is long gone.

“The Vega drive is smooth, ridiculously smooth.”

Astronomers were shocked then Webb and Hubble showed nothing to indicate that any major planets were going about their work, plow away dustwhich would be typical for a star system as old as Vega, only about 10 percent of it the sun. Usually these nubile stars are surrounded by a lot of dust, enriched by frequent collisions asteroids And comets.

Hubble detects material the size of smoke particles, and Webb can pick up particles as small as a grain of sand, according to NASA. But neither showed up signs of worlds pushing away and clearing dust, a clue scientists look for when trying to determine whether a star has planets. The discovery of a pancake disk with no obvious signs of planets forces them to rethink why Vega’s system isn’t what they expected, and it could provide new insights into planet formationin 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

“It’s different from other circumstellar disks we’ve looked at,” Andras Gáspár, another member of the research team, said in a statement. “The Vega drive is smooth, ridiculously smooth.”

Despite the smoothness, the disc seems to have that a small, subtle gap far away from the star, about double Neptune’s distance from the Sun. The researchers say this rules out the possibility of planets at the very 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 – ostensibly the building blocks for making planets – could harbor life.

“Vega remains unusual,” Schuyler Wolff, lead author of the study, said in a statement. “The architecture of the Vega system is clearly different from our own solar system, where giant planets like Jupiter and Saturn prevent the dust from spreading like Vega.”