Researchers Measure a Brown Dwarf’s Wind Speed Using Jupiter as Model

Brown dwarfs are cosmic half-ways, as they can be categorized neither as planets nor as stars. Researchers believe that getting more information about their atmospheres could aid them in their attempt to learn about massive planets orbiting other stars.

For the first time, scientists have accurately calculated the speed of the wind on a brown dwarf, a body more massive than Jupiter, but not that gigantic to become a star. To get the results, the experts employed a new technique that could also be applied to understand the atmosphere of gas-filled planets outside our Solar System.

Measuring the Wind Speed of a Faraway Brown Dwarf

The research was published in the journal Science and merges observations by a series of radio telescopes with data from NASA‘s recently expired infrared observatory, the Spitzer Space Telescope, controlled by the Jet Propulsion Laboratory (JPL).

Officially dubbed 2MASS J10475385+2124234, the brown dwarf is located about 32 light-years from Earth. The scientists identified winds traveling around the cosmic body, at 1,425 mph (2,293 kph).

Calculating the speed of the wind on Earth means measuring the motion of the gaseous atmosphere in comparison to the planet’s surface. But brown dwarfs are made out of mostly gas, so ‘wind’ here refers to something a bit different.

The upper sheets of a brown dwarf are where areas of the gas are able to move unbothered. At a particular depth, the pressure becomes so powerful that the gas acts like a single, solid ball that is deemed as the object’s inner part. As this interior orbits, it pulls the upper layers – or the atmosphere – along, so the two are almost in sync.

In their research, the team of scientists measured the small difference in speed of the brown dwarf’s atmosphere in comparison to its interior. Having an atmosphere temperature of more than 1,100 degrees Fahrenheit (600 degrees Celsius), this cosmic body emits a generous amount of infrared light.

Combined with its close distance to our planet, those factors made it possible for Spitzer to identify features in the brown dwarf’s upper layer, and they fluctuate in and out of view. The researchers then used those features to measure the atmospheric rotation speed.

Using Jupiter

In order to get its measurements right, the team tested the method using infrared and radio observations of Jupiter, which is also mostly made out of gas and has a physical shape similar to that of a small brown dwarf.

Researchers compared the orbit rates of Jupiter’s atmosphere and inner part using data that was rather similar to what they gathered for the brown dwarf. The calculations for the planet’s wind speed were confirmed by employing more accurate data captured by spacecraft that have analyzed Jupiter up close, therefore, proving that their approach for the brown dwarf functioned.

“We think this technique could be really valuable to providing insight into the dynamics of exoplanet atmospheres,” said lead author Katelyn Allers, an associate professor of physics and astronomy at Bucknell University in Lewisburg, Pennsylvania. “What’s really exciting is being able to learn about how the chemistry, the atmospheric dynamics and the environment around an object are interconnected, and the prospect of getting a really comprehensive view into these worlds.”

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