Trans-Neptunian Objects (TNOs) are small planetoids that orbit the Sun beyond Neptune and Pluto, holding secrets of the early solar system. A new study using the James Webb Space Telescope has analyzed 54 TNOs’ spectra, grouping them into three categories based on their surface characteristics.
The researchers identified three types: Double-dip TNOs with high carbon dioxide ice content, Cliff-type TNOs rich in nitrogen molecules and complex organics, and Bowl-type TNOs with dark, dusty surfaces and water ice. The authors propose that these categories formed due to “ice lines” existing during the early solar system period, where temperatures allowed for specific types of ice to form at different distances from the Sun.
This theory is supported by a correlation between spectral category and orbital type, with cold classical TNOs often belonging to the Cliff-type category. The study also connects TNOs to centaurs, a type of planetoid orbiting between Jupiter and Saturn, finding that some centaurs match specific TNO categories. This suggests that many centaur planetoids were once TNOs that migrated inward over time, while others are comets that became centaurs after close approaches with Jupiter or Saturn.
Further studies with more detailed spectra could reveal the specific histories of each TNO category and their connection to the early solar system’s evolution.
Source: https://www.universetoday.com/170273/the-webb-captures-spectra-of-trans-neptunian-objects-and-reveals-a-history-of-our-solar-system