Winds of 1,500 MPH Recorded on 'Failed Star' 33 Light-Years Away in First Observation of Its Kind

For the first time, astronomers have measured atmospheric wind speed on a world outside our solar system, recording winds averaging around 1,450 mph on a brown dwarf—an astronomical object with a mass between that of a planet and a star.

Previously, scientists have only been able to measure wind speeds within our solar system, but a novel approach enabled an international team of researchers to do what no one has been able to do before, according to a study published in the journal Science.

"While we have long been able to directly probe the atmospheres and winds of the bodies in our own solar system, we've had to conjecture what they're like in other kinds of bodies, and if there's one thing we've learned from our studies of extrasolar bodies thus far, it's that our primary conjectures often turn out to be wrong," Peter Williams, an author of the study of the Harvard-Smithsonian Center for Astrophysics, said in a statement.

"This new technique opens the way to better understanding the behavior of atmospheres that are unlike anything found in our solar system," he said.

The team was able to measure the wind speed on a brown dwarf known as 2MASS J1047+21 located around 33 light-years from Earth. It is roughly the same size as Jupiter but 40 times more massive.

They did this by combining radio observations from the National Science Foundation's Karl G. Jansky Very Large Array (VLA) observatory and infrared observations from NASA's Spitzer Space Telescope.

"In order to attempt our measurement, we needed to study a brown dwarf that had two special characteristics: it needed to have measurable variability at the infrared wavelengths, and it needed to be a known emitter of radio pulses. If you go through what we currently know from prior observations, it becomes pretty clear the 2MASS 1047+21 is one of the top targets to try," Williams told Newsweek.

Brown dwarfs are sometimes referred to as "failed stars" because they are more massive than planets, but not massive enough to generate the kinds of thermonuclear reactions in their cores that power true stars.

"Since we don't have any examples of [brown dwarfs] right in our solar system, there's a lot that we don't understand about them—which makes them interesting to us!" Williams told Newsweek.

But despite a lack of knowledge, scientists think brown dwarfs share many of the same rotational and atmospheric characteristics as gas giant planets, like Jupiter and Saturn in our own solar system.

For these relatively nearby worlds, astronomers can determine the speed of winds in their atmospheres by comparing the movement of clouds to the radio emissions caused by the rotation of their interiors. Because brown dwarfs are expected to share several similarities to gas giants, the team adapted this technique for use on the distant brown dwarf.

"Brown dwarfs have atmospheres but they're pretty different than Earth's—they can be completely covered in clouds made out of several different chemicals, not just water," Williams told Newsweek. "Even though brown dwarfs are too far away for us to pick out individual clouds when we observe them, we can still measure how long it takes a group of clouds to do a lap around the atmosphere, on average. 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."

"In this project, we measured this lap time and wanted to find out the wind speed. In order to do this, we needed another measurement: how fast the brown dwarf was spinning. It turns out that in some brown dwarfs it's possible to measure this spin rate by detecting radio waves that they give off: in the right circumstances, we observe a pulse of radio waves every time the brown dwarf rotates," he said.

brown dwarf, magnetic field
Artist's conception of a brown dwarf and its magnetic field. Bill Saxton, NRAO/AUI/NSF

This is because the radio waves come from high-energy particles trapped in the brown dwarf's magnetic field, and its magnetic field is rooted deep in its interior—just like the Earth—where there's no "wind" to alter the measurement.

By taking the difference of the cloud lap time and the radio pulse time, the team worked out that the distant world featured high wind speeds with an average speed of 660 meters per second, or around 1,450 miles per hour, although numbers between about 600 and 2,200 mph could all be consistent with the available data.

These winds whip around the brown dwarf "eastward," meaning that the atmosphere is rotating faster than the interior—just like Jupiter—according to the researchers. This finding is consistent with most of the theories of brown dwarfs that scientists haven't been able to confirm until now.

Despite the similarities with Jupiter though, the wind speeds on 2MASS 1047+21 are much higher than on the gas giant where the winds "only" reach speeds of around 230 mph.

"This agrees with theory and simulations that predict higher wind speeds in brown dwarfs," Katelyn Allers, lead author of the study from Bucknell University, said in a statement.

According to the astronomers, the latest research could have significant implications given that the novel technique could be used to measure winds on other brown dwarfs and even some exoplanets, casting new light on our understanding of distant worlds.

"The takeaway that I'm excited about is that we've shown that you can take this technique that's previously only been used in our own solar system, and apply it to distant objects. That's pretty cool!" Williams said. "While this first measurement does rule out some unusual theories, I'm more excited about the prospects for the future."

"We've shown that the technique works, and now we can start applying it to more objects and trying to get more precise numbers. What would be really exciting—but is definitely a long way off—would be to apply it to exoplanets as well as brown dwarfs. The needed measurements are going to be very challenging, because exoplanets are not only fainter than brown dwarfs, but they're also right next to their big bright parent stars. But the principles are the same and we think we'll be able to do it one day," he said.