University of Coimbra scientist helps discover 'Neptunian Ridge'
The finding was published today in the journal Astronomy & Astrophysics, unveiling the complex processes that occur in the 'Neptunian Desert'—an area around stars where Neptune-like exoplanets are rarely found—and the ‘Neptunian Savanna,’ a region further from stars where these planets are more commonly observed.
An international team of scientists, including Alexandre Correia, a researcher at the Centre for Physics of the University of Coimbra (CFisUC), has discovered the "Neptunian Ridge," a new feature in the landscape of Neptune-type exoplanets.
The finding was published today in the journal Astronomy & Astrophysics, unveiling the complex processes that occur in the 'Neptunian Desert'—an area around stars where Neptune-like exoplanets are rarely found—and the ‘Neptunian Savanna,’ a region further from stars where these planets are more commonly observed.
“Our study focuses on the boundaries of the Neptunian Desert and its transition into the Savanna, where we found an unexpected concentration of planets, forming a sharp dividing line between the two regions, which we called the 'Neptunian Ridge,'” says Alexandre Correia, co-author of the study and professor at the Department of Physics, Faculty of Sciences and Technology, University of Coimbra.
“We found that a large number of Neptunian planets orbit their stars in periods between 3 and 6 days. We are about eight times more likely to find a planet in this region than in a shorter orbit (in the desert) and about three times more likely to find a planet in a longer orbit (in the savanna), suggesting that these planets have undergone different evolutionary processes,” explains Amadeo Castro-González, researcher at the Centre for Astrobiology (CAB), INTA-CSIC, and first author of the study.
The discovery was made possible by analysing data from NASA's Kepler mission using advanced statistical techniques. Researchers meticulously mapped the exoplanets' radius-period relationship, unveiling distinct regions that define the new Neptunian landscape. This detailed mapping reveals the complex processes involved in the migration and atmospheric evaporation of these planets.
The authors interpreted the results in the context of theories of planet formation and evolution and concluded that the accumulation of planets in the Neptunian Ridge region can be explained by the existence of two distinct migration mechanisms that populate the Ridge and the Savanna.
The scientific article “Mapping the Exo-Neptunian landscape. A ridge between the desert and savanna” is a collaboration between the Centre for Astrobiology (CAB) and the Universities of Coimbra, Geneva, Paris and Warwick, and is available here.