'They're kind of goth': NASA spacecraft gives mysterious brown dwarfs a close-up

Astronomers using NASA’s SPHEREx spacecraft have analyzed the chemical makeup of brown dwarfs, mysterious cosmic bodies that sit between planets and stars. Sometimes called failed stars, these objects form from collapsing gas clouds like stars but lack the mass to trigger hydrogen fusion in their cores. The research team examined 37 nearby brown dwarfs using data spanning 102 light wavelengths, from deep red to invisible infrared.

These objects ranged in temperature from 4,000 degrees Fahrenheit down to minus 10 degrees Fahrenheit. The SPHEREx observations revealed atmospheres rich in water, carbon dioxide, carbon monoxide, and methane. Because Earth's atmosphere absorbs specific light wavelengths, the orbital telescope captured details that ground-based instruments miss. Study leader Zafar Rustamkulov of Caltech noted that the chemical makeup of these isolated worlds resembles our solar system's gas giants.

While current models match general chemical trends, researchers reported that models struggle to match data during cloudy atmospheric transitions. Published on Sept. 28 in The Astrophysical Journal, the study evaluated just three dozen brown dwarfs, but researchers are currently analyzing thousands more to better understand their varied atmospheres and evolution.