What can a star’s behavior teach scientists about the formation and evolution of sub-Neptune exoplanets, which comprise one of the most discovered exoplanets? This is what a recent study published in The Astronomical Journal hopes to address as an international team of researchers the evolution of short-period exoplanets, which are exoplanets that orbit their star in 12 days or less. This study has the potential to help researchers better understand the formation and evolution of exoplanets throughout the cosmos and how this could influence the search for life beyond Earth.
For the study, the researchers analyzed data obtained from NASA’s Transiting Exoplanet Survey Satellite mission for short-period exoplanets with radii between 1.8- and 10-times Earth while orbiting 1,374 F-, G-, and K-type stars. For context, our Sun, is a G-type star, with F-type stars being larger and hotter while K-type stars are smaller and cooler.
The goal of the study was to ascertain how losing their atmospheres from orbiting so close to their stars could influence their formation and evolution. In the end, the researchers determined that the star’s growth over time could influence the orbits and radii of sub-Neptunes, including causing them to travel towards the star, resulting in the short period orbits they experience today.
“It’s possible that many sub-Neptunes originally formed further away from their stars and slowly migrated inward over time, so we see more of them at this orbital period in the intermediate age,” said Dr. Rachel Fernandes, who is a President’s Postdoctoral Fellow at Penn State University and lead author of the study. “In later years, it’s possible that planets are more commonly shrinking when radiation from the star essentially blows away its atmosphere, a process called atmospheric mass loss that could explain the lower frequency of sub-Neptunes. But it’s likely a combination of cosmic processes shaping these patterns over time rather than one dominant force.”
Artistic diagram depicting the evolution of short-period exoplanets with an emphasis on their orbits becoming closer to their star while losing their atmospheres to the intense radiation. (Credit: Abigail Minnich (abbyminnich.wixsite.com/film))
This study comes as NASA has confirmed the existence of more than 5,800 exoplanets, with almost 75 percent being found using the transit method, which is typically used to identify short-period exoplanets. Therefore, this study could help astronomers better understand the formation and evolution of short-period exoplanets and whether they could perhaps support life as we know it, or even as we don’t know it.
What new discoveries about sub-Neptune exoplanets will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: The Astronomical Journal, EurekAlert!, Penn State Eberly College of Science
