Unraveling the Enigma of Mounds in the Kuiper Belt: A Common Origin for Arrokoth’s Grand Structures?

A recent investigation, led by Dr. Alan Stern, a Planetary Scientist and Associate Vice President at Southwest Research Institute (SwRI), sheds light on the strikingly similar mound formations that grace one of the lobes of the Kuiper Belt object known as Arrokoth. These enigmatic mounds, each approximately 5 kilometers in length, hint at a shared origin, potentially holding the key to understanding the streaming instability model of planetesimal formation.

Intriguingly, the SwRI study suggests that these mound structures, often likened to building blocks, might offer valuable insights for the development of planetesimal formation models. Dr. Stern presented these groundbreaking findings at the 55th Annual Division for Planetary Sciences (DPS) meeting hosted by the American Astronomical Society in San Antonio. The research findings were formally published on September 26 in the esteemed Planetary Science Journal.

A Glimpse from NASA’s Perspective

The genesis of this investigation traces back to 2019 when NASA’s New Horizons spacecraft embarked on a close encounter with Arrokoth. During this mission, Dr. Stern and his colleagues meticulously analyzed the data and uncovered a remarkable discovery – the presence of 12 remarkably similar mounds on Arrokoth’s larger lobe, Wenu. These mounds exhibited striking resemblances in shape, size, color, and reflectivity. Moreover, they tentatively identified three additional mounds on the object’s smaller lobe, Weeyo.

The Preservation of Arrokoth’s History

What sets Arrokoth apart is its exceptional preservation, allowing scientists to discern the intricate details of its assembly. Lowell Observatory’s Dr. Will Grundy, a co-investigator of the New Horizons mission, aptly described Arrokoth as resembling a raspberry, comprised of these small, uniform sub-units.

Supporting the Streaming Instability Model

Arrokoth’s geological features offer compelling support for the streaming instability model of planetesimal formation. This model suggests that objects accumulate gently at low collision speeds, forming larger structures like Arrokoth within local regions of the solar nebula undergoing gravitational collapse.

The Significance of Similarities

Dr. Stern, who serves as the Principal Investigator of the New Horizons mission, emphasizes the significance of the similarities observed in Arrokoth’s mound structures. He notes that if these mounds indeed represent the building blocks of ancient planetesimals like Arrokoth, it becomes imperative for planetesimal formation models to account for the preferred size of these building blocks.

Looking to the Future

With upcoming missions such as NASA’s Lucy mission to Jupiter’s Trojan asteroids and ESA’s comet interceptor, there’s a promising prospect of encountering other pristine planetesimals. These encounters could deepen our understanding of planetesimal accretion in the ancient solar system and shed light on potential variations from the processes observed in the Kuiper Belt.

Dr. Stern highlights the importance of scrutinizing other planetesimals for mound-like structures to gauge the prevalence of this phenomenon, offering further insights into planetesimal formation theories.

In Conclusion

The research conducted by Dr. Alan Stern and his team has unveiled intriguing insights into the mysterious mounds of Arrokoth, potentially reshaping our understanding of planetesimal formation. As we await further exploration and analysis, Arrokoth and its enigmatic mounds continue to captivate the scientific community, inviting us to delve deeper into the rich history of our solar system.

Reference: “The Properties and Origin of Kuiper Belt Object Arrokoth’s Large Mounds” by S. A. Stern, O. L. White, W. M. Grundy, B. A. Keeney, J. D. Hofgartner, D. Nesvorný, W. B. McKinnon, D. C. Richardson, J. C. Marohnic, A. J. Verbiscer, S. D. Benecchi, P. M. Schenk and J. M. Moore, 26 September 2023, The Planetary Science Journal.
DOI: 10.3847/PSJ/acf317

The New Horizons spacecraft, designed and operated by The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, is managed by NASA’s Science Mission Directorate. Southwest Research Institute, headquartered in San Antonio, oversees the mission under the guidance of Principal Investigator Stern, who leads the science team, payload operations, and encounter science planning. New Horizons is a pivotal component of NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.

Frequently Asked Questions (FAQs) about Kuiper Belt Mound Formation

More about Kuiper Belt Mound Formation

• The Planetary Science Journal: The published research paper detailing the properties and origin of Arrokoth’s large mounds.
• American Astronomical Society: Information about the 55th Annual Division for Planetary Sciences (DPS) meeting where the findings were presented.
• NASA New Horizons Mission: Information about NASA’s New Horizons spacecraft and its mission to explore the Kuiper Belt, including Arrokoth.
• Southwest Research Institute (SwRI): The institution where Dr. Alan Stern, the lead scientist, is affiliated, providing additional information about their research efforts in planetary science.
• Kuiper Belt: Background information about the Kuiper Belt, the region of the solar system where Arrokoth is located.