How Giant Impacts Generate Seismic Vibrations That Last for Millions of Years

The Moon gives us a glimpse into the chaotic history of our Solar System. Its surface, dotted with craters, shows evidence of countless collisions. Early solar systems likely experienced similar turbulence, filled with debris and impacts.

Researchers recently explored these violent beginnings by simulating a clash between two massive gas giants. They found that some exoplanets could hold cores with over 100 Earth masses, formed through numerous collisions with smaller planetesimals, each about 10 Earth masses.

In this study, titled “Seismic Oscillations Excited by Giant Impacts in Directly-Imaged Giant Planets.,” lead author J.J. Zanazzi, a theoretical physicist from UC Berkeley, investigates how giant impacts might create lasting seismic waves.

The key questions are whether these impacts produce significant seismic waves and if they can be detected by the James Webb Space Telescope (JWST). While the JWST cannot directly measure seismic waves, it can observe light changes. If seismic activity is strong enough, the JWST can pick up these changes through precise photometric measurements.

According to the authors, “In principle, planet-scale impacts could excite seismic oscillations in directly imaged exoplanets.” They focus on **Beta Pictoris b**, a young exoplanet that is a super-Jupiter, with about 13 Jupiter masses and only 12 to 20 million years old. Research has shown this planet is rich in metals, possibly due to a process called “strong planetesimal enrichment.”

Beta Pictoris b is especially fascinating because it contains between 100 and 300 Earth masses of heavy metals. The researchers simulated a collision between Beta Pictoris b and a Neptune-mass planet with 17 Earth masses. Their findings suggest that heavy metal accumulation in giant exoplanets mainly results from such collisions. They also noted that seismic activity is likely to last as long as the planet’s age.

When seismic waves occur, they can cause variations in the planet’s brightness, which the JWST could detect if a collision took place in the last 9 to 18 million years. This method offers an intriguing way to explore exoplanet interiors, with seismology providing direct insights into these distant worlds.

Additionally, the authors believe their findings could help identify planetary migrations. They point out that impacts are not the only forces creating these oscillations; other factors like tidal forces from a host star can excite these waves in hot and warm Jupiters, adding further layers to our understanding of planet formation and dynamics.

This research paints a clear picture of how the violent beginnings of gas giants can have lasting consequences. As we continue to study these cosmic giants, tools like the JWST will allow us to uncover even more secrets hidden within the depths of our universe.

For further insights, you can read the original piece published by Universe Today here.

Source link