In the intricate dance of celestial bodies, new findings have unveiled a previously overlooked chapter in the formation of planets. Researchers, led by Alice Quillen, Professor of Astronomy and Astrophysics at the University of Rochester, have delved into the dynamics of planetesimals, the precursors to planets, in their tumultuous journey within protosolar nebulae.

The study, titled “Wind erosion and transport on planetesimals,” published in the journal Icarus, sheds light on the influence of headwinds composed of gas and particles within the protosolar disk. Before the birth of stars, protosolar disks host countless planetesimals, ranging from 10 to 100 km in diameter.

Contrary to the conventional narrative of planetesimals gradually amalgamating to form planets, the research unveils a new dimension. As these small bodies navigate the chaotic protosolar nebula, they encounter headwinds, not from stellar winds but from the gas and dust within the disk itself.

The headwinds, arising from differences in velocity, temperature, and pressure within the protosolar disk, exhibit the power to dislodge rocky debris from the planetesimals. This phenomenon challenges the notion of a smooth accretion process, revealing that aeolian (wind-driven) processes play a crucial role.

The study identifies that on planetesimals with a diameter of 10 km in the inner Solar System, the headwind can lift particles as small as centimeters off their surfaces. In the outer Solar System, the interaction results in the removal of micron-sized particles, either tossed into space or redeposited on the planetesimal.

For planetesimals below 6 km in diameter, the process leads to erosion rather than accretion. Factors such as wind velocity, headwind particle size, and material size become pivotal in determining the outcome of this intricate planetary formation ballet.

Quillen and her team point to the well-known Kuiper Belt Object, Arrokoth, as a potential example shaped by protostellar disk winds. Arrokoth’s smooth surface, unlike other Jupiter family comets, aligns with conditions of low-velocity winds and abundant particles.

The research underscores that aeolian processes can significantly alter the surfaces of planetesimals, introducing a dynamic element to our understanding of planetary formation. The distance from the protostar emerges as a key variable, with erosion or accretion rates higher in the inner solar system where the protosolar disk density is greater.

As we continue to unravel the intricacies of celestial evolution, these findings open the door to further exploration and deeper insights into the cosmic forces shaping our celestial neighborhood. Future studies are anticipated to delve into the multitude of phenomena arising from the interplay between particle-rich headwinds and planetesimals, offering a richer understanding of the celestial symphony that orchestrates the formation of planets.