This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Scientists from Trinity College Dublin have developed a way to unravel changing weather patterns on distant worlds. Using this approach, they discovered that the weather on a well-studied brown dwarf, SIMP 0136, previously linked to northern lights-like phenomena, is largely shaped by just two dominant processes: changes in temperature and the vertical structure of its clouds.
Using observations from NASA's James Webb Space Telescope (JWST), the team applied a statistical technique called principal component analysis (PCA) to track how the object's light changes as it rotates. PCA simplifies complex data by identifying the main patterns that change together across observations. In this study, those dominant patterns are linked to weather-related changes in the brown dwarf's atmosphere, allowing researchers to distinguish them from smaller fluctuations and random "noise" in the data.
Rather than relying on complex assumptions about its atmosphere, the method allowed the researchers to identify the key physical processes directly from the data. The data showed minute changes in the brightness of the planetary-mass object as it rotated, which were made detectable by the exceptional sensitivity of JWST's instruments. The vast majority of the atmospheric variability could be explained by only two dominant components, consistent with changes in temperature and the vertical structure of clouds.
This insight reveals an atmosphere whose observed changes can be explained by three recurring weather states that rotate in and out of view, producing a patchwork of hotter, thinner-cloud regions alongside cooler areas with thicker, vertically extended clouds. The new research, published in the journal Astronomy & Astrophysics, suggests that, despite its apparent complexity, the atmosphere of SIMP 0136 behaves in a remarkably organized way rather than reorganizing randomly. The brown dwarf is a world larger and hotter than a gas giant planet but not massive enough to shine like a star.
Its atmosphere is dominated by huge, fast-changing cloud systems. In that sense, it is less like Earth and more like an extreme version of Jupiter, with planet-sized weather patterns constantly reshaping what astronomers see. "We also discovered that these drivers of the weather patterns on SIMP 0136 persist over time, even as the detailed appearance of the atmosphere evolves over more than a dozen rotations," said first author Merle Schrader, a Ph.D. candidate in Trinity's School of Physics.
"In relative terms, SIMP 0136 is one of the easier brown dwarfs for us to capture high-quality data from. These data have been studied before by established methods, allowing us to compare some of the results from this new technique to what we already know about this object. The technique has also helped us develop a better understanding of what drives the weather on this faraway world and how these weather patterns interact and coexist, but perhaps even more importantly, it shows how this approach can be further refined and applied to other, less well-known brown dwarfs in different parts of space." There is a personal connection for Schrader and her test subject, SIMP 0136, which is 20 light-years (about 189 trillion km, 117 trillion miles) from Earth.
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