James Webb Spots Mysterious Object Crossing Space Between Stars

Yahoo

05-03-2025

NASA's groundbreaking James Webb Space Telescope has spotted a mysterious object that's freely floating through interstellar space.
According to NASA, the "planetary-mass" object, dubbed SIMP 0136, is roughly 13 times the mass of Jupiter, and is located just 20 light-years from Earth. It's also spinning at a breakneck speed, completing a full rotation every 2.4 hours.
Thanks to the JWST's detailed infrared light observations, an international team of researchers detected signs of "complex atmospheric features," including possible cloud layers and temperature shifts in the object's atmosphere, as detailed in a study they published in the journal The Astrophysical Journal Letters.
It's a fascinating glimpse at an exceedingly rare object. The researchers suggest in their paper that objects like SIMP 0136 could much in common with cloud giants in the solar system, like Jupiter and Saturn, which "also have multiple cloud layers and high-altitude hot spots" (except that it's floating through space without a star, that is.) Astronomers also aren't ruling out the possibility that it's a brown dwarf, an object that's between a planet and a star.
The latest research builds on existing observations by NASA's Hubble and Spitzer space telescopes.
"We already knew that it varies in brightness, and we were confident that there are patchy cloud layers that rotate in and out of view and evolve over time," said lead author and Boston University doctoral student Allison McCarthy in a NASA statement. "We also thought there could be temperature variations, chemical reactions, and possibly some effects of auroral activity affecting the brightness, but we weren't sure."
James Webb's Near-Infrared Spectrograph allowed scientists to observe a much wider spectrum of infrared light, leading to fascinating new insights into the lonely object.
"Until now, we only had a little slice of the near-infrared spectrum from Hubble, and a few brightness measurements from Spitzer," said principal investigator and Trinity College Dublin assistant professor Johanna Vos in the statement.
The researchers ran hundreds of detailed light curves against atmospheric models to get a better sense of what SIMP 0136's atmosphere might look like.
They found evidence for patchy clouds and bright "hot spots," possibly related to auroras, far above the clouds.
"Imagine watching Earth from far away," Boston University scientist and coauthor Philip Muirhead said in a statement. "If you were to look at each color separately, you would see different patterns that tell you something about its surface and atmosphere, even if you couldn't make out the individual features."
"Blue would increase as oceans rotate into view," he added. "Changes in brown and green would tell you something about soil and vegetation."
Other light curves observed by the JWST suggest the existence of pockets of carbon monoxide and carbon dioxide — but plenty of questions remain.
"We haven't really figured out the chemistry part of the puzzle yet," Vos said. "But these results are really exciting because they are showing us that the abundances of molecules like methane and carbon dioxide could change from place to place and over time."
"If we are looking at an exoplanet and can get only one measurement, we need to consider that it might not be representative of the entire planet," she added.
More on brown dwarfs: Astronomers Discover Brown Dwarf Covered in Stripes