TEHRAN (Iran News) – Scientists have been able to measure the wind speed on an object outside of our solar system for the first time.
The object, known as a brown dwarf, is 33.2 light-years away from Earth.
Brown dwarfs aren’t quite stars, but they’re not planets either. These so-called “failed stars” are too big to be planets. The brown dwarf in this study is the size of Jupiter, the largest planet in our solar system, but it has 40 times the mass of Jupiter, CNN reported.
On the nearby cool brown dwarf 2MASS J1047+21, scientists clocked wind speeds reaching 1,450 miles per hour. The study published Thursday in the journal Science.
Previously, scientists have only been able to measure wind speeds on planets and bodies in our solar system. The new findings ruled out models that were used to guess wind speeds outside of our solar system.
“This new technique opens the way to better understanding the behavior of atmospheres that are unlike anything found in our solar system,” said Peter Williams, study author and innovation scientist for the Center for Astrophysics collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory.
The measurement was made using a new technique that combined the detection of radio and infrared emissions. This allowed scientists to know the wind speed of a distant object, even though they couldn’t pick out cloud movement in its atmosphere.
“On Earth, for example, say you have a cloud being blown by some wind,” said Katelyn Allers, study co-author and physics and astronomy professor at Bucknell University.
“If you’re looking down at Earth from space, you could measure the speed of a continent as it rotates in and out of view and a different speed for the cloud as it rotates in and out of view. And that difference in speed occurs because the wind has pushed that cloud relative to the surface,” Allers said.
Distant brown dwarfs and exoplanets, or planets outside of our solar system, are a little more complicated.
“We can’t see the clouds themselves, but when a cloud rotates into view or out of view, it changes the brightness of the planet,” she said.
“Even though brown dwarfs are completely covered in clouds, they’re too far away for us to pick out individual clouds like we do on planets within our solar system. But we can still measure how long it takes for a group of clouds to do a lap around the atmosphere; as clouds come in and out of view they change the brightness of the planet,” Williams said.
“This lap time depends on two things: how fast the brown dwarf itself is spinning, and how fast the wind is blowing on top of that.”
Data from NASA’s recently retired Spitzer Space Telescope, as well as from the National Science Foundation’s Karl G. Jansky Very Large Array of telescopes in New Mexico, was crucial for the measurement. The scientists were able to monitor the brightness of the brown dwarf and track its changes.
Because the brown dwarf is cold, it emits infrared light. Spitzer, an infrared telescope, was designed to pick up its signal. The Jansky array allowed them to use radiowaves to determine the rotation beneath the atmosphere by detecting the planet’s magnetic field.
“Since the magnetic field originates deep in the planet, or in this case brown dwarf, the radio data allows us to determine the interior period of rotation,” Allers said. “When you have an interior rotation rate and an atmospheric rotation rate, you can compare them to see how fast the wind is blowing.”
Similar to Jupiter, this brown dwarf’s atmosphere is rotating faster than its interior. But Jupiter’s wind speeds max out at 230 miles per hour — slow and steady compared to the screaming winds of the brown dwarf.
But the 1,450 miles per hour clocked speed agrees with previous predictions by astronomers that brown dwarfs would have high winds.
This new technique developed during the study could be used to measure wind speeds on other brown dwarfs and exoplanets as well, the researchers said.
“We’re excited that our method can now be used to help us better understand the atmospheric dynamics of brown dwarfs and extrasolar planets,” Allers said.
- source : Tasnim, Irannews