Astronomers Discover Giant Exoplanet with Molten Iron Rain
An international team of astronomers has made a groundbreaking discovery, conducting a detailed study of a giant exoplanet where rocks vaporize and rain down molten iron. The planet, known as WASP-76 b, orbits the massive star WASP-76, located approximately 634 light-years away in the constellation Pisces.
WASP-76 b is classified as a “hot Jupiter” due to its close proximity to its parent star. It orbits about 12 times closer to its star than the planet Mercury does to the sun. Despite its similarity in mass to Jupiter, WASP-76 b is six times more massive.
The exoplanet’s extreme temperatures, reaching around 2,400 degrees Celsius (4,350 degrees Fahrenheit), are hot enough to vaporize iron. This led the team of astronomers to identify 11 chemical elements in the planet’s atmosphere and measure their abundance. Surprisingly, some of these elements have not been measured in the gas giants of our own solar system, such as Saturn and Jupiter.
“This study provides us with a rare opportunity to learn something potentially impossible to know about our solar system from an exoplanet hundreds of light-years away,” said Stéphane Pelletier, the team leader from the University of Montreal’s Trottier Institute for Exoplanet Research.
The unique properties of WASP-76 b, including its close orbit and tidal restriction, result in a perpetual day side that is constantly hot and a perpetual night side that is much cooler. The temperature difference between the two sides leads to strong winds, reaching speeds of up to 18,000 km per hour, which transport elements in the planet’s atmosphere from one side to the other.
Using the MAROON-X high-resolution optical spectrometer at the Gemini Observatory in Hawaii, astronomers were able to study the formation of “hot Jupiter” in unprecedented detail. The intense temperatures on WASP-76 b cause elements like magnesium and iron, which would normally be rocks on terrestrial planets, to evaporate and accumulate as gases in the planet’s upper atmosphere.
This study provides astronomers with valuable insights into the presence and abundance of rock-forming elements in the atmospheres of giant planets. Cooler giant planets like Jupiter do not allow for the detection of these elements, as they are located too low in the atmosphere.
The team also found that the abundances of certain elements in WASP-76 b’s atmosphere closely matched those in its host star and our own sun. This suggests that the composition of the exoplanet is similar to the protoplanetary disk of matter that collapsed into its birth, potentially indicating a common composition among giant planets.
However, the team also discovered some unexpected findings. Certain elements in the exoplanet’s atmosphere appeared to be “depleted,” indicating sensitivity to temperature. Depending on the temperature, elements can either exist as gases in the upper atmosphere or condense into liquids and sink into the lower layers, making their detection challenging.
Another significant discovery was the presence of vanadium oxide in WASP-76 b’s atmosphere. This chemical compound plays a similar role to ozone in Earth’s atmosphere and can have a significant impact on heating the upper atmosphere of hot giant planets.
Additionally, the team found a higher abundance of nickel than expected around WASP-76 b, suggesting that the giant planet may have swallowed a smaller, Mercury-like Earth at some point in its history.
The research paper detailing these findings was published in the journal Nature, shedding light on the fascinating and complex nature of exoplanets and their atmospheres.
wasp-76b
E to analyze the light emitted by the planet and its parent star. They found a distinctive spectral signature of iron vapor in the exoplanet’s atmosphere, indicating the presence of molten iron rain.
The discovery of molten iron rain on WASP-76 b is significant because it provides valuable insights into the dynamics and composition of exoplanets. This phenomenon is believed to occur due to the extreme temperature gradient between the day and night sides of the planet, causing the precipitation of condensed iron droplets.
The study’s findings also shed light on the chemical composition of WASP-76 b’s atmosphere. The astronomers identified 11 different chemical elements, some of which have not been observed in gas giants within our own solar system.
Stéphane Pelletier, the team leader from the University of Montreal’s Trottier Institute for Exoplanet Research, explained that this study provides a unique opportunity to gain insights into our own solar system through an exoplanet located hundreds of light-years away.
The extreme temperatures and atmospheric dynamics of WASP-76 b make it a fascinating object of study for astronomers. The perpetual day side and night side, with their stark temperature differences, give rise to powerful winds that transport elements across the planet’s atmosphere. These winds can reach speeds of up to 18,000 km per hour.
To conduct their research, the team used the MAROON-X high-resolution optical spectrometer at the Gemini Observatory in Hawaii. This instrument enabled them to analyze the light emitted by both the exoplanet and its parent star, leading to the detection of the iron vapor and molten iron rain.
Overall, the discovery of the giant exoplanet WASP-76 b and its unique properties, including molten iron rain, provides valuable insights into the composition, dynamics, and atmospheric processes of these distant worlds. It highlights the importance of studying exoplanets to deepen our understanding of planetary systems beyond our own.