Exploring the Neptunian Desert
Astronomers have launched a new program called ATREIDES to study what is known as the “Neptunian Desert” in space. Unlike typical deserts, this desert represents the absence of planets with masses around 20 times that of Earth, orbiting close to their stars. These planets are referred to by scientists as “hot Neptunes.”
What is the Neptunian Desert?
The Neptunian Desert is a region in space where hot Neptunian planets are scarce. These planets are characterized by their large mass and high temperatures due to their proximity to their stars. However, their rarity in the universe raises many questions about their formation and evolution.
In an attempt to understand this phenomenon, scientists are studying the planetary system TOI-421, which includes an orange dwarf star orbited by two planets, TOI-421 b and TOI-421 c. These planets exhibit unusually tilted orbits, suggesting a chaotic history for this system.
The TOI-421 Planetary System
The TOI-421 system is located about 244 light-years from Earth. The planets in this system show unusually tilted orbits, indicating a chaotic history that may explain the scarcity of hot Neptunes. The planet TOI-421 b is a hot sub-Neptune with a mass seven times that of Earth, orbiting very close to its star.
The planet TOI-421 c is larger, with a mass about 14 times that of Earth, and orbits at a slightly greater distance, making it a hot Neptune located in an area known as the “savanna” adjacent to the Neptunian Desert.
Understanding Different Regions in Space
In addition to the Neptunian Desert, scientists have identified two other regions: the savanna and the Neptunian hills. The savanna is an area with a higher number of Neptunian planets, while the Neptunian hills are denser with planets than both regions.
The ATREIDES program aims to understand the processes that lead to the formation of these diverse regions. Hypotheses suggest that these regions may have resulted from the migration of planets from their formation sites to the orbits we observe today.
Planetary Migration and Its Impact
Planetary migration is considered a crucial factor in shaping planetary systems. Some planets migrate slowly within the gas and dust disk surrounding a young star. This slow migration can result in orbits aligned with the star’s equator.
Conversely, some planets may be violently ejected from their formation sites through a process known as “high-eccentricity migration,” leading to orbits that are not aligned with the star’s equator.
Conclusion
The ATREIDES program represents a new and important step in understanding the Neptunian Desert and its neighboring regions. Although the results are not yet conclusive, current research demonstrates the program’s effectiveness and the methods it employs. By studying more planetary systems containing hot Neptunes, astronomers can gain a deeper understanding of planetary evolution in the universe.