New observations from NASA’s Transiting Exoplanet Survey Satellite (TESS) have revealed the presence of high-speed jets, zonal circulation and polar vortices on Luhman 16B, one of the closest brown dwarfs to the Sun.
An artist’s conception of the binary system Luhman 16AB with the Sun in the background. Image credit: Janella Williams / Penn State University.
Luhman 16B is a member of the binary brown-dwarf system Luhman 16AB, which is located 6.5 light-years away in the southern constellation of Vela.
Also known as WISE 1049-5319, the system was discovered by Pennsylvania State University’s Professor Kevin Luhman using NASA’s Wide-field Infrared Survey Explorer.
Luhman 16A is about 34 times more massive than Jupiter. Luhman 16B is 28 times more massive than Jupiter.
These brown dwarfs are between 600 and 800 million years old. They orbit each other at a distance of about 3.5 AU with an orbital period of 27 years.
In new research, Dr. Daniel Apai from the University of Arizona and colleagues used TESS to observe Luhman 16A and B.
“We wondered, do brown dwarfs look like Jupiter, with its regular belts and bands shaped by large, parallel, longitudinal jets, or will they be dominated by an ever-changing pattern of gigantic storms known as vortices like those found on Jupiter’s poles?” Dr. Apai said.
The astronomers found that Luhman 16B looks strikingly similar to Jupiter. The patterns in its atmosphere reveal high-speed winds running parallel to the brown drawf’s equator.
These winds are mixing the atmosphere, redistributing heat that emerges from the brown dwarf’s hot interior. Also, like Jupiter, vortices dominate the object’s polar regions.
“Some atmospheric models predicted this atmospheric pattern,” Dr. Apai said.
“Wind patterns and large-scale atmospheric circulation often have profound effects on planetary atmospheres, from Earth’s climate to Jupiter’s appearance, and now we know that such large-scale atmospheric jets also shape brown dwarf atmospheres.”
“Knowing how the winds blow and redistribute heat in one of the best-studied and closest brown dwarfs helps us to understand the climates, temperature extremes and evolution of brown dwarfs in general.”
The results show that there is a lot of similarity between the atmospheric circulation of solar system planets and brown dwarfs.
As a result, brown dwarfs can serve as more massive analogs of giant planets existing outside of our Solar System in future studies.
“Our study provides a template for future studies of similar objects on how to explore — and even map — the atmospheres of brown dwarfs and giant extrasolar planets without the need for telescopes powerful enough to resolve them visually,” Dr. Apai said.
The study was published in the Astrophysical Journal.
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Dániel Apai et al. 2021. TESS Observations of the Luhman 16 AB Brown Dwarf System: Rotational Periods, Lightcurve Evolution, and Zonal Circulation. ApJ 906, 64; doi: 10.3847/1538-4357/abcb97
