We finally have a close-up look at 'failed stars'
What's the story
NASA's SPHEREx spacecraft has given astronomers a close-up look at a group of enigmatic cosmic bodies known as brown dwarfs or "failed stars." These strange entities sit somewhere between planets and stars, with a mass ranging from 13 to 80 times that of Jupiter. They are called failed stars because they form like stars but don't have enough mass to ignite hydrogen fusion in their cores, the process that powers real stars.
Celestial isolation
The cosmic loners
Brown dwarfs are often described as cosmic loners, drifting through the dark void of space without the light of a parent star.
Their atmospheres are chemically similar to those of our solar system's gas giant planets.
"They're kind of goth," said Zafar Rustamkulov from Caltech.
He added that unlike exoplanets, free-floating brown dwarfs are completely independent celestial objects that will fade into eternity alone.
Advanced observation
SPHEREx's unique capabilities
SPHEREx, short for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer, can detect light wavelengths that ground-based telescopes can't.
This is because Earth's atmosphere absorbs these wavelengths.
Rustamkulov said they are "picking up light from the deep, red clouds of brown dwarfs all over the sky."
The team studied 37 nearby brown dwarfs across a spectrum of light including 102 wavelengths.
Chemical composition
Insights into diversity of brown dwarfs
The spectra of brown dwarfs observed by SPHEREx revealed that their atmospheres are rich in water, carbon dioxide, carbon monoxide, and methane.
"We're seeing the signatures of these molecules and how they change from object to object across the entire temperature regime," said J. Davy Kirkpatrick from Caltech.
The team has thousands more brown dwarfs to analyze and hopes to learn more about their diversity in the universe.
Observational advantage
Unraveling mysteries of brown dwarfs
SPHEREx's wide wavelength coverage has made it especially useful for observing brown dwarfs.
Some of these failed stars are at an extreme stage of change, with their clouds clearing and atmospheres rich in methane.
However, state-of-the-art models are struggling to match the data when it comes to these cloudy transitions.
"No two brown dwarfs are alike," Rustamkulov said, emphasizing their unique nature even at the same temperature.