Located just 25 light-years away from Earth, the phenomena surrounding Vega may revolutionize our understanding of how extraterrestrial worlds form.
The James Webb Space Telescope has captured a remarkably smooth disk of cosmic debris surrounding Vega, a bright blue supergiant star, which is the brightest in the Lyra constellation.
This is a massive protoplanetary disk, similar to the protoplanetary disk of the early solar system, where Earth and other planets originated.
However, the protoplanetary disk around Vega exhibits characteristics that scientists describe as “unexplainable.”
The protoplanetary disk surrounding Vega is remarkably smooth – (Image credit: UNIVERSITY OF ARIZONA).
A research team from the Steward Observatory – Lunar and Planetary Laboratory at the University of Arizona, the Space Sciences Institute, NASA’s Jet Propulsion Laboratory, and Trinity College Dublin has studied this unusual structure.
Protoplanetary disks are expected to have gaps, which are the locations where gas and dust accumulate to form planets.
However, according to Dr. Andras Gáspár from the University of Arizona, the disk of Vega is unusually smooth, indicating that no planets exist around it.
There is a faint band located about 60 astronomical units (AU, where 1 AU is the distance from the Sun to Earth) from the star.
Upon closer examination, this is merely the result of a small amount of dust being blown further away by radiation, rather than evidence of a forming planet.
Although Vega is much younger than the Sun—approximately 455 million years old—it is old enough to have produced planets. For comparison, our Earth is estimated to be less than 10 million years younger than the Sun.
When comparing Vega to Fomalhaut, a slightly younger star, the peculiarity of Vega’s smooth disk becomes even more evident.
Fomalhaut is a perfect counterpart to Vega; it is also a bright blue-white star with a significant gap in its protoplanetary disk, indicating that a giant planet or several smaller planets have formed.
Researchers are puzzled as to why Vega appears incapable of forming exoplanets while Fomalhaut seems able to do so, despite the existence of similar physical mechanisms in both star systems.
The researchers have proposed several scenarios, but none adequately explain why Vega cannot form planets.
They also wonder whether there are many other disks in the universe that do not form exoplanets in such a smooth manner.
If such disks are common, calculations regarding the number of planets that could exist in the galaxy or the universe could be profoundly altered.
“This makes us rethink the scope and diversity among exoplanetary systems,” concluded Dr. Kate Su from the University of Arizona.
