Examining the exoplanet Tylos: Astronomers have discovered by looking through an exoplanet’s atmosphere and mapping its 3D structure for the first time
Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), scientists have discovered powerful winds carrying elements like iron and titanium, showing complex weather patterns that challenge our current understanding of the planetary atmosphere.
This study of the planet WASP-121b, also known as Tylos, opens up new possibilities for studying distant alien worlds’ chemical makeup and weather systems.
Atmosphere mapping of the exoplanet Tylos
Located 900 light-years away in the constellation Puppis, Tylos is an ultra-hot Jupiter, a gas giant orbiting extremely close to its host star.
A year on this planet lasts just about 30 Earth hours. This extreme proximity to the star results in one side of the planet being perpetually scorched while the other remains much cooler. Studying this new world has provided scientists with the first detailed, 3D map of an exoplanet’s atmosphere, revealing complex layers of winds and dynamic weather patterns never seen before outside our Solar System.
The research team discovered that a jet stream encircles the planet\s equator, while at lower atmospheric levels, another flow of gas moves from the hot side to the cooler side.
This interaction of atmospheric flows creates a climate unlike anything observed on other planets. The jet stream, which spans half the planet, swirls violently as it crosses the intensely hot side of Tylos. The strength of these winds is such that they are far more intense than even the most powerful hurricanes within our own Solar System. This weather behavior opens up new avenues for understanding how atmospheric dynamics can work in extreme environments.
A world with extreme weather
To reveal the 3D structure of the planet’s atmosphere, the team used the ESPRESSO instrument on the VLT. By combining the light from four telescope units into a single signal, the instrument can gather four times the amount of light as a single telescope, providing the ability to detect even the faintest details.
Observing Tylos as it passed in front of its star, the team was able to identify the signatures of various chemical elements, allowing them to probe different layers of the atmosphere. They tracked the movements of iron, sodium, and hydrogen, revealing the dynamics of winds at varying depths within the atmosphere.
This observation is particularly impressive as it can study multiple layers of the atmosphere simultaneously.
The VLT’s capabilities allowed the team to trace the winds in the deep, mid, and shallow layers of Tylos’s atmosphere in a single observation.
This approach shows a step forward in studying exoplanet atmospheres, as similar observations are typically challenging to perform with space-based telescopes.
One of the most unexpected findings came from the discovery of titanium in the atmosphere just beneath the jet stream. Previous observations had suggested that this element was absent from the planet, possibly hidden deep within the atmosphere. However, this new study shows that titanium is present in surprising amounts, providing a new layer of complexity to our understanding of Tylos’s atmospheric composition.
The future of exoplanet exploration
In the future, the study of smaller, Earth-like planets will require even more advanced technology.
The ESO’s Extremely Large Telescope (ELT), currently under construction in Chile, will be essential in these efforts. With its powerful instruments, the ELT will offer new abilities for studying the atmospheres of exoplanets in more detail than ever before. As astronomers continue to study alien worlds, the discoveries made using the VLT show just the beginning of a new era in exoplanet research, with more groundbreaking findings expected shortly.
