What can sub-Neptunes, exoplanets whose sizes are between Earth and Neptune, and which are between the known for their water-rich compositions, teach astronomers about both where and how to find life beyond Earth? This is what a recent study published in The Astrophysical Journal hopes to address as an international team of scientists led by the University of California, Santa Cruz (UCSC) investigated the formation and evolution of sub-Neptunes. This study has the potential to help scientists better understand these mysterious worlds and whether they could hold the ingredients for life as we know it.
For the study, the researchers used a series of computer models to simulate the processes responsible for the formation and evolution of sub-Neptunes, specifically the planetary radius and how this results in the present-day planetary compositions. In the end, the researchers found that sub-Neptunes surrounded by large amounts of atmospheric water, also called water envelopes, are predicted to exist on planets with small radii. Additionally, they discovered that water residing within the deep interiors of sub-Neptunes is colder than previously hypothesized.
“The interiors of planets are natural ‘laboratories’ for studying conditions that are difficult to reproduce in a university laboratory on Earth,” said Dr. Natalie Batalha, who is a Professor in UCSC’s Astronomy & Astrophysics Department and a co-author on the study. “What we learn could have unforeseen applications we haven’t even considered. The water worlds are especially exotic in this sense. In the future, we may find that a subset of these water worlds represent new niches for life in the galaxy.”
Going forward, the researchers aspire to use NASA’s powerful James Webb Space Telescope to observe sub-Neptunes with the goal of verifying or refuting the model’s results. The reason sub-Neptunes are of importance for finding life beyond Earth is their watery compositions, since on Earth water means life. Additionally, sub-Neptunes could be large enough to have exomoons that could mimic moons of our solar system like Europa, Titan, or Enceladus.
What new discoveries about sub-Neptunes 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 Astrophysical Journal, EurekAlert!
Featured Image: Artist's illustration of a sub-Neptune. (Credit: Hubble/M.Kornmesser/ESA)