New observations from the NASA/ESA/CSA James Webb Space Telescope support the presence of three specific functions in the atmosphere (clouds, hot spots, and changes in carbon chemistry) of the rapidly rotating and free floating planetary mass object SIMP J013656.5+093347.
SIMP J013656.5+093347 (SIMP 0136 for short) is a rapidly rotating, free-floating object located just 20 light years from Earth.
It may have a mass of 13 Jupiter masses, does not orbit the star, and instead may be a brown dwarf.
Because it is separated, SIMP 0136 can be directly observed and is not afraid of mild contamination or variability caused by the host star.
The short rotation period, only 2.4 hours, allows for very efficient investigation.
“We've been working hard to get into the world,” said Allison McCarthy, a doctoral student at Boston University.
“We also thought that it might have an effect on temperature fluctuations, chemical reactions, and perhaps the activity of the aurora affecting brightness, but we weren't sure.”
Webb's NirSpec Instruments We captured thousands to 5.3 micron spectra of SIMP 0136. The object completed one full rotation, so I captured it one at a time, one at a time, one at a time, one at a time, over 3 hours.
This led to immediate observation Webb's Milli Musical Instrumentshundreds of measurements of light between 5 and 14 microns were collected. One is one every 19.2 seconds, one in another rotation.
The results were hundreds of detailed rays, each showing a very accurate wavelength (color) brightness change, with different sides of the object rotating into view.
“It was incredible to see the entire range of this object change over a few minutes,” said Dr. Joanna Foss, an astronomer at Trinity College Dublin.
“Until now, we only had a small near-infrared spectrum from Hubble, but we had some brightness measurements from Spitzer.”
Astronomers almost immediately noticed that there were several distinct ray shapes.
At any time, some wavelengths were growing brightly, while others were either dimmed or not changing at all.
Many different factors must affect brightness variation.
“Imagine looking at the Earth from afar,” said Dr. Philip Muirhead, a former member of Boston University.
“Looking each color individually gives you a variety of patterns that tell you something about the surface and the atmosphere, even if you don't understand the individual features.”
“As the ocean rotates towards vision, blue increases. The brown and green changes tell us something about the soil and vegetation.”
To understand what could cause variability in SIMP 0136, the team used an atmospheric model to show where each wavelength of light is occurring in the atmosphere.
“The different wavelengths provide information about the different depths in the atmosphere,” McCarthy said.
“We began to realize that the wavelengths that had the most similar ray shapes also investigated the same depth and reinforced this idea that they must be caused by the same mechanism.”
For example, one group of wavelengths occurs deeply in the atmosphere where there may be patchy clouds made of iron particles.
The second group comes from high clouds, which are thought to be made from small grains of silicate minerals.
Both of these light curve variations are related to the patchiness of the cloud layers.
The third group of wavelengths appears to be occurring at very high altitudes far above the clouds and tracking temperatures.
Bright hotspots may be associated with previously detected auroras at radio wavelengths, or hot gas upwelling from deeper in the atmosphere.
Some light curves cannot be explained by clouds or temperature, but instead show variations related to atmospheric carbon chemistry.
There may be chemical reactions in which carbon monoxide and carbon dioxide pockets rotate within and outside of view, or alter the atmosphere.
“We still don't understand the chemical part of the puzzle yet,” Dr. Vos said.
“But these results are really exciting because they show that the richness of molecules like methane and carbon dioxide can change over time from location.”
“If you're looking at a deplanet and only have one measurement, you should assume that it may not be representative of the entire planet.”
Survey results It will be displayed in Astrophysics Journal Letter.
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Allison M. McCarthy et al. 2025. JWST weather report from isolated exoplanet analog SIMP 0136+0933: pressure-dependent variability driven by multiple mechanisms. apjl 981, L22; doi: 10.3847/2041-8213/AD9EAF
Source: www.sci.news
