An illustration of the planetary-mass object SIMP 0136
Photo Credit: NOIRLab/NSF/AURA/J. da Silva
A detailed investigation of an isolated planetary-mass object has been conducted using the James Webb Space Telescope (JWST), revealing critical atmospheric insights. Located approximately 20 light-years from Earth, SIMP 0136 has drawn significant interest due to its ambiguous nature—floating freely without a parent star and possessing characteristics that align both with planets and failed stars. Its mass is estimated to be around 13 times that of Jupiter, yet its size remains similar. The object's rapid rotation results in a day lasting just 2.4 Earth hours.
Findings of the Study
According to research published in The Astrophysical Journal Letters, SIMP 0136 could either be a rogue planet or a brown dwarf, a celestial body that forms like a star but lacks sufficient mass to sustain hydrogen fusion. The JWST's observations, carried out across two full rotations, provided unprecedented details about its atmospheric composition.
The study was led by Allison McCarthy, a researcher at Boston University. Speaking in an official statement, she mentioned that previous investigations had indicated brightness variations, suggesting dynamic atmospheric activity. The JWST's Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI) allowed the team to capture detailed infrared light curves, revealing how different wavelengths fluctuated over time.
As reported, multiple layers within the atmosphere were identified, each displaying distinct properties. One wavelength group indicated the presence of patchy iron clouds at lower altitudes, while another suggested silicate clouds higher up. Some brightness variations observed could not be explained solely by cloud cover, hinting at chemical reactions or auroral activity.
Principal investigator Johanna Vos of Trinity College Dublin told that this level of spectral variation had never been observed before. The team is now working to decode the role of methane and carbon dioxide, as their concentrations appear to shift across different atmospheric regions.
New Analysis Weakens Claims of Life on Distant Exoplanet K2-18b29 May 2025
Search
