Scientists measure wind speed in a brown dwarf


A team of American and British researchers used data collected by NASA’s Spitzer Space Telescope and the Very Large Array radio telescope (VLA), of the National Science Foundation Karl G. Jansky, to calculate how fast winds circulate in a (almost) star. This is the first time that this type of measurement has been performed and, as you might imagine, the wind in stars like these is rough!

The star in question consists of a brown dwarf cataloged as 2MASS J10475385 + 2124234 and which is about 34 light-years away from Earth. This star is similar in size to Jupiter’s, except that it is about 40 times more massive – and does not have enough mass to house the thermonuclear reactions that normally occur in the nuclei of stars themselves.

This means that brown dwarfs are, in a nutshell, quasi-stars often referred to as “failed stars”. The fact is that, in order to calculate how fast the winds circulate through the dwarf, in addition to examining the observations conducted by the telescopes we mentioned earlier, the scientists also relied on studies related to gas giants that make up the Solar System.

More specifically, the researchers took into account observations made on Jupiter that pointed out disparities in its rotational period. Radio telescopes captured emissions produced by the interaction between electrons and the planet’s magnetic field, originating further inland, revealing a rotational period, while observations conducted at wavelengths in the visible and infrared range, focused on the outermost layers of the Jupiter atmosphere, pointed to a different period.

These surveys, in turn, helped scientists to demonstrate that the planet’s atmosphere “spins” faster than its inner region, as well as to model the dynamics of winds on Jupiter – which can reach 370 kilometers per hour and are partially responsible for such a difference in the orbital period.

Anyway, the scientists decided to apply the same reasoning to observe what the dynamics would look like in the brown dwarf. Because, after conducting similar observations, the researchers found that there were also differences between the speed of rotation of the outermost layers of the atmosphere and its interior – and that the winds blow in the “quasi-star” at almost 2,300 kilometers per hour . Have you thought about how it shouldn’t be in a real star?

The cool thing about the study is that this same method can be used to help measure wind in other “failed stars” and also in exoplanets – in addition to helping scientists better understand how atmospheric mechanisms work in distant stars.


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