In a recent study published in the journal Nature Astronomy, researchers Peter L. Olson from the University of California, Davis, Zachary D. Sharp from the University of New Mexico, and Susmita Garai from the University of California, Davis, have shed light on the depletion of moderately volatile elements during the formation of Earth-like planets. Their findings have implications for understanding the composition of terrestrial planets and the processes that shape their atmospheres.
The researchers focused on the process of pebble accretion, where protoplanets grow by capturing small, pebble-sized particles from the surrounding nebula. As these pebbles settle through the protoplanet’s atmosphere, they release gravitational potential energy, heating both the atmosphere and the pebbles themselves. This heating can lead to the melting of silicate pebbles and the evaporation of volatile species, which are then lost to the nebula.
The study found that the depletion of moderately volatile elements such as sodium, potassium, and zinc depends critically on the mass of the protoplanet, the timescale of atmosphere exhaust, and the composition of the pebbles. For example, substantial depletion of zinc begins around 0.4 Earth mass, and for sodium and potassium around 0.6 Earth mass, with negligible depletion at smaller masses. The researchers also found that a protoplanetary mass of approximately 0.7 Earth mass, combined with one or more smaller, less-depleted impactors, can broadly reproduce Earth’s depletion trend for moderately volatile elements.
These findings have practical applications for the energy sector, particularly in the field of planetary resources. Understanding the composition of terrestrial planets and the processes that shape their atmospheres can help identify potential sources of valuable resources, such as rare earth elements and other minerals. This knowledge can inform the development of space mining technologies and the exploration of new energy sources beyond Earth.
The study also highlights the importance of considering the dynamic and complex processes that occur during planetary formation. By better understanding these processes, we can gain insights into the potential habitability of exoplanets and the possibility of finding Earth-like planets with similar compositions and atmospheres. This research was published in Nature Astronomy, a leading journal in the field of astronomy and planetary science.
This article is based on research available at arXiv.