Going Rogue

Earth’s auroras may be an awesome sight to see but these bright, colorful lights also highlight important details about a planet’s atmosphere and evolution, according to a new study. 

Astronomers recently analyzed data collected by NASA’s James Webb Space Telescope (JWST) to study SIMP-0136, a rogue planet located about 20 light-years from Earth. 

The faraway world has a mass about 12.7 times that of Jupiter and belongs to a group of planets that do not orbit any star, known as “free-floating” planets.  

For their paper, the research team sought to understand how this rogue planet’s atmosphere behaves and how auroras affect it to gain new clues about planetary formation and evolution in worlds untethered to stars. 

Because SIMP-0136 has a rotational period of 2.4 hours, researchers were able to observe all aspects of the planet, according to Universe Today. 

Their analysis showed a few peculiarities of SIMP-0136 that make it the complete opposite of Earth. 

The rogue planet’s atmosphere exhibits “thermal inversion,” which means that its upper atmosphere is hotter than the world’s surface – in contrast to Earth, where atmospheric temperature gets colder with increasing altitude. 

Average temperatures on the planet are more than 2,700 degrees Fahrenheit, with researchers saying the culprit behind this searing heat is its auroras. 

SIMP-0136’s auroras are powered by magnetic interactions and charged particles – instead of sunlight, such as on Earth – demonstrating that even starless planets can produce extreme weather and atmospheric heating.  

The findings also showed that SIMP-0136 had constant cloud coverage and its clouds are made up of silicate grains – similar to beach sand. 

The study builds on a previous paper earlier this year that showed clouds, hot spots, and carbon chemistry variations on SIMP-0136 but lacked explanations for their cause. 

“These are some of the most precise measurements of the atmosphere of any extra-solar object to date, and the first time that changes in the atmospheric properties have been directly measured,” lead author Evert Nasedkin explained in a statement. 

Nasedkin and his colleagues hope that the new findings and future data collected by JWST will shed more light on rogue planets floating in the cosmos.  

“Understanding these weather processes will be crucial as we continue to discover and characterize exoplanets in the future,” he added. 

First discovered in 2000, rogue planets have fascinated astronomers, who are still speculating about their formation and evolution. Questions remain whether they were ejected from their original star systems or if they are sub-brown dwarf stars.  

Although the exact figure hasn’t been established, scientists believe there could be billions to trillions of rogue planets in our Milky Way Galaxy.