Disney Plus Deal Alert: Get 72% Off Now

A Spectrum of Clues

Using the James Webb Space Telescope (JWST), astronomers have peered into the atmosphere of a cosmic body that could be a rogue planet or a “failed star.” Either way, the world wanders the cosmos without a parent. The cosmic orphan, or “free-floating planetary-mass object,” designated SIMP 0136 drifts through the universe around 20 light-years from Earth — and it does so without a stellar anchor. SIMP 0136 has a mass that’s around 13 times the mass of Jupiter, but it is around the same size as the solar system gas giant.

Discovered in 2003, SIMP 0136 rotates so rapidly that a day on this rogue world lasts just around 2.4 Earth hours. There is a possibility that SIMP 0136 isn’t a planet at all but is an object called a “brown dwarf,” a stellar body that forms like a star but fails to gather enough mass to trigger the nuclear fusion of hydrogen to helium in its core. The confusion arises from the fact that these “failed stars” have a lower mass limit of around 13 times the mass of Jupiter — right around the mass of SIMP 0136, in fact.

Because SIMP 0136 is relatively bright for an isolated planetary mass object and its light isn’t contaminated by the light of a parent star, it has been a popular target for astronomers. Thus, even before the JWST examined this object, a range of ground-based instruments as well as the Hubble and Spitzer space telescopes had studied it. These investigations, however, left astronomers with some puzzles surrounding SIMP 0136.

Astronomers had previously discovered that SIMP 0136 fluctuates in brightness. It was reasoned that these changes couldn’t simply be the result of clouds on the Jupiter-size world alone, but rather have to do with a complex combination of atmospheric factors. Using the JWST, the team was able to monitor infrared light from SIMP 0136 for two full rotations, observing variations in the world’s cloud layers, temperature and even its chemistry. Many of the details the scientists observed were previously hidden from view.

Hidden Rainbows and Temperature Shifts

“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,” Allison McCarthy, study team leader and a researcher at Boston University, said in a 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.”

Observing SIMP 0136 with the JWST over two rotations allowed the team to use the telescope’s Near-Infrared Spectrograph (NIRSpec) as well as its Mid-Infrared Instrument (MIRI). This meant the researchers could collect data in a wide range of wavelengths of infrared light. The result was hundreds of highly detailed light curves showing how each wavelength of infrared light changed in brightness as SIMP 0136 rotated. “To see the full spectrum of this object change over the course of minutes was incredible,” Johanna Vos , the team’s principal investigator and a researcher at Trinity College Dublin, said in the statement. “Until now, we only had a little slice of the near-infrared spectrum from Hubble, and a few brightness measurements from Spitzer.”

The researchers noticed that the infrared light from SIMP 0136 had distinct light curve shapes, with some wavelengths brightening while others dimmed; the rest did not change at all. They reasoned there must be various factors influencing these variations. “Imagine watching Earth from far away. If you were to look at each color separately, you would see different patterns that tell you so much about what’s happening in the atmosphere,” Vos explained. “Similarly, by looking at different wavelengths of infrared light from SIMP 0136, we can learn about the different layers of its atmosphere and how they are responding to changes in temperature and composition.”

These observations suggest the presence of distinct atmospheric layers, each with its own characteristics and responding uniquely to changes. This observation hints at the possibility of “invisible rainbows” formed by infrared light interacting with atmospheric particles. These infrared rainbows would be invisible to our eyes but could be detected by JWST’s instruments.

Chemical Fingerprints and Auroral Effects

Analyzing the spectral data allows astronomers to identify the chemical elements present in SIMP 0136’s atmosphere. JWST’s sensitivity and ability to observe a wide range of wavelengths provide a much more detailed picture of the atmospheric composition than previous observations. This detailed chemical fingerprint can provide clues about the object’s formation and evolution. For example, the presence of certain elements, like water vapor or methane, could indicate the object’s history and potential for harboring life.

Furthermore, variations in brightness might be linked to auroral activity, similar to the auroras observed on Earth. Auroras are caused by charged particles from the Sun interacting with a planet’s magnetic field. If SIMP 0136 has a magnetic field, auroral activity could explain some of the brightness fluctuations observed by JWST. Studying these auroras could provide insights into the object’s magnetic field strength and structure.

The JWST findings are a significant step forward in understanding these enigmatic objects. They highlight the power of JWST to probe the atmospheres of distant worlds and uncover their secrets.

Implications for Understanding Planetary Formation and Evolution

Challenging Our Understanding of Brown Dwarfs

SIMP 0136’s characteristics challenge existing models of brown dwarf formation and evolution. Its mass and brightness raise questions about the boundary between planets and stars and how these objects form and evolve under different conditions. The traditional view is that brown dwarfs form in a similar way to stars, but they don’t have enough mass to ignite sustained nuclear fusion. However, SIMP 0136’s brightness suggests it might be more massive than previously thought, blurring the lines between planets and brown dwarfs. This finding could require astronomers to revise their understanding of the formation and evolution of both types of objects.

Galactic Wanderers and Atmospheric Processes

Studying rogue planets and brown dwarfs like SIMP 0136 provides valuable insights into the diverse processes shaping planetary systems and the evolution of atmospheres in extreme environments. These objects are essentially “cosmic orphans,” having been ejected from their natal star systems. This allows them to evolve in isolation, providing a unique window into the processes that govern planetary atmospheres without the influence of a parent star.

Future Exploration

JWST’s observations have paved the way for future studies of SIMP 0136, potentially revealing even more about its internal structure, magnetic field, and the processes occurring within its atmosphere. Future observations with JWST and other telescopes could help astronomers better understand the nature of SIMP 0136 and its place in the broader context of planetary formation and evolution.