A recent study published in the journal Astronomy & Astrophysics has shed light on the formation of Neptune and other celestial bodies in the outer reaches of our solar system. The study focuses on a binary duo named Mors-Somnus, which consists of a pair of icy asteroids bound by gravity and orbits just beyond Neptune in the Kuiper Belt. This discovery presents an exciting opportunity to enhance our understanding of the dynamical history of Neptune and other objects known as trans-Neptunian objects (TNOs).

The research, led by Ana Carolina de Souza Feliciano and Noemí Pinilla-Alonso from the University of Central Florida (UCF), is part of the Discovering the Surface Compositions of Trans-Neptunian Objects program (DiSCo-TNOs). This program utilizes the James Webb Space Telescope’s (JWST) advanced capabilities to analyze the solar system’s outer regions. The study marks the first time that the surface composition of a binary pair of small-sized TNOs has been thoroughly examined, providing valuable insights into the region beyond Neptune.

The findings reveal that Mors-Somnus shares similar spectral properties with other TNOs in its vicinity, particularly those designated as “cold classical.” These TNOs are believed to have been undisturbed by Neptune during its migration, making them crucial reference points for understanding the history of the outer solar system. The study suggests that the binary objects and nearby TNOs could provide clues about Neptune’s migration before settling into its current orbit.

The researchers also identified complex organic materials, CO₂, CO, OH-compounds, and tentative nitrogen-rich materials in the spectra of Mors and Somnus. These compositional similarities with other TNOs hint at the survival of the plutino binary from the early population of objects beyond 30 astronomical units. The study’s results provide compelling evidence for evaluating Neptune’s migration in the trans-Neptunian region during the early stages of the solar system’s history.

This groundbreaking research not only deepens our understanding of the formation and evolution of the outer solar system but also paves the way for future discoveries using the unprecedented spectral capabilities of the JWST. The study’s findings have significant implications for planetary science, offering valuable insights into the origin of celestial bodies and the distribution of molecules that contributed to the formation of planets, moons, and even the origin of life and water on Earth.

References

• Duryea, E. & University of Central Florida. (2024, March 6). Scientists use James Webb Space Telescope to uncover clues about Neptune’s evolution. Phys.Org; University of Central Florida. https://phys.org/news/2024-03-scientists-james-webb-space-telescope.html
• Souza-Feliciano, A. C., Holler, B. J., Pinilla-Alonso, N., De Prá, M., Brunetto, R., Müller, T., Stansberry, J., Licandro, J., Emery, J. P., Henault, E., Guilbert-Lepoutre, A., Pendleton, Y., Cruikshank, D., Schambeau, C., Bannister, M., Peixinho, N., McClure, L., Harvison, B., & Lorenzi, V. (2024). Spectroscopy of the binary TNO Mors–Somnus with the JWST and its relationship to the cold classical and plutino subpopulations observed in the DiSCo-TNO project. Astronomy & Astrophysics, 681, L17. https://doi.org/10.1051/0004-6361/202348222