Summary: Astronomers have discovered iron winds blowing across the dayside of WASP-76 b, an ultra-hot exoplanet, providing new insights into extreme planetary atmospheres and climate dynamics.
Estimated reading time: 4 minutes
In a fascinating development, astronomers have detected iron winds blowing across the scorching dayside of WASP-76 b, an ultra-hot gas giant exoplanet. This discovery sheds new light on the complex atmospheric dynamics of distant worlds and pushes the boundaries of our understanding of planetary climates.
Why it matters: The study of extreme exoplanets like WASP-76 b helps scientists better understand the diversity of planetary environments in the universe and refine models of atmospheric behavior under intense conditions.
Unveiling the secrets of a hellish world
WASP-76 b, discovered in 2013, has captivated researchers with its extreme conditions. Located about 640 light-years from Earth in the constellation Pisces, this “ultra-hot Jupiter” orbits perilously close to its host star. Its dayside temperature soars to a blistering 2,400 degrees Celsius (4,352 degrees Fahrenheit) – hot enough to vaporize metals.
An international team of astronomers, including scientists from the University of Geneva (UNIGE) and the PlanetS National Centre of Competence in Research, used the powerful ESPRESSO spectrograph on the Very Large Telescope in Chile to study WASP-76 b’s atmosphere in unprecedented detail.
“This is the first time that such detailed optical observations have been made on the day side of this exoplanet, providing key data on its atmospheric structure,” explains Ana Rita Costa Silva, a doctoral student at the Instituto de Astrofísica e Ciências do Espaço (IA) and first author of the study published in Astronomy & Astrophysics.
Winds of iron and extreme weather
The researchers detected a stream of iron atoms moving from lower to upper layers of WASP-76 b’s atmosphere on its dayside. This iron wind is likely driven by intense heating from the planet’s host star, creating a hot spot in the atmosphere.
“Our observations indicate the presence of powerful iron winds, probably fuelled by a hot spot in the atmosphere,” Costa Silva adds.
This discovery adds to the growing list of extreme phenomena observed on WASP-76 b. Previous studies have found evidence of iron rain on the planet’s cooler nightside, the presence of barium in its upper atmosphere, and even a “rainbow” effect at the boundary between day and night.
Advanced technology unlocks cosmic mysteries
The breakthrough was made possible by the ESPRESSO spectrograph, an instrument renowned for its precision and stability. Built largely by UNIGE and installed on the VLT, ESPRESSO allowed the team to acquire high-resolution spectra of the planet and identify the chemical signatures of moving iron in its atmosphere.
Christophe Lovis, associate professor in the Astronomy Department at UNIGE and co-author of the study, emphasizes the importance of this technology: “ESPRESSO’s ability to make such precise measurements is crucial. This level of precision allows us to explore the dynamic processes in the atmospheres of exoplanets like WASP-76 b with an unprecedented level of detail.”
Implications for understanding planetary climates
The study of WASP-76 b and similar ultra-hot gas giants provides valuable insights into the extremes of planetary climates. By mapping atmospheric winds and chemical compositions in detail, astronomers are developing more comprehensive models of how these distant worlds evolve.
David Ehrenreich, associate professor in the Astronomy Department at UNIGE and co-author of the study, explains: “The work on WASP-76 b shows us just how extreme atmospheric conditions can be on ultra-hot Jupiters. In-depth analysis of this type of planet provides us with valuable information for a better understanding of planetary climates as a whole.”
As researchers continue to probe the mysteries of WASP-76 b and other exotic worlds, they inch closer to a more complete understanding of the diverse planetary environments that exist in our galaxy and beyond.
Quiz: Test Your Knowledge of WASP-76 b
- What is the approximate dayside temperature of WASP-76 b? a) 1,000°C b) 1,500°C c) 2,400°C d) 3,000°C
- Which instrument was crucial in detecting the iron winds on WASP-76 b? a) Hubble Space Telescope b) ESPRESSO spectrograph c) James Webb Space Telescope d) Kepler Space Telescope
- What previous phenomenon had been observed on WASP-76 b’s nightside? a) Methane storms b) Iron rain c) Water geysers d) Diamond clouds
Answer Key:
- c) 2,400°C
- b) ESPRESSO spectrograph
- b) Iron rain
