The (geo)scientific news of the week (or of the last week)

2025 week 3

K2-22b: A disintegrating rocky exoplanet shrouded in dust and gas, studied using JWST

Nick Tussay and colleagues have shown that the ultra-short-period rocky exoplanet K2-22b, which is currently disintegrating, periodically emits dust clouds in a dynamic and chaotic process, resulting in transit depth variations of between 0 and 1.3%. These emissions, resulting from sublimation of its surface, could reflect the composition of the inner layers transported to the molten surface. The team used the MIRI instrument on the James Webb Space Telescope (JWST) to observe four predicted transits of K2-22b in the spectral range 4.3 to 11.8 μm.

One transit was detected with high significance and two others with lower significance. The results show that:

1. Iron-rich materials (characterizing planetary cores) are unlikely.

2. The data are consistent with magnesium silicates from the mantle.

3. An unexpected spectral feature around 5 μm was identified, possibly related to gases such as NO or CO₂.

https://doi.org/10.48550/arXiv.2501.08301

 

2025 week 2

A New Look at Tornadoes: Measuring the Invisible with Atmospheric Muons

Tornadoes are extreme weather events that occur when a violently rotating column of air connects the ground to a thunderstorm. Hundreds of tornadoes strike the United States each year. However, the precise mechanisms of their formation and propagation remain poorly understood. One of the main challenges is the deployment of measurement instruments: current detectors, often in situ, are difficult to use near an active or developing tornado.

William Luszczak and Leigh Orf explore a novel approach by combining local simulations of the atmosphere and cosmic ray showers to assess the potential of atmospheric muons to remotely measure the density field in tornado-generating supercells.

(https://journals.aps.org/prd/abstract/10.1103/PhysRevD.111.023018)

 

2024 Latest News

About 70% of the meteorites come from three recent collisions of asteroids larger than 30 km in diameter.

 

Understanding the origin of shooting stars and their meteorite samples has long been a central question in astronomy. To date, only 6% of meteorite falls have been clearly attributed to sources such as the Moon, Mars, or the asteroid Vesta. However, a new study reveals that about 70% of meteorites originate from three recent asteroid collisions larger than 30 km, occurring 5.8, 7.6, and less than 40 million years ago. These events, including the famous Karin family, explain the prevalence of ordinary H and L chondrites among meteorite falls.