NASA has identified 17 exoplanets outside our solar system that likely have hidden oceans beneath their icy surfaces. These oceans could potentially harbor life.
Key Details About The Discovery
- The exoplanets are a range of sizes, from Earth-sized to larger than Neptune.
- They orbit red dwarf, orange dwarf or brown dwarf stars.
- Models indicate they have temperatures well below freezing on their surfaces.
- However, the inside of the planets could be warm enough to have oceans of liquid water.
- These oceans would be hidden beneath layers of surface ice several miles thick.
- On some of these icy worlds, subsurface oceans may erupt from below as geysers on hotspots.
“We may have found several oceans’ worth of water in these planets,” stated lead researcher Lynnae Quick, a planetary scientist at NASA’s Goddard Space Flight Center. “It’s fascinating to imagine oceans hidden below many frozen exoplanet surfaces.”
How The Discovery Was Made
Quick and colleagues utilized archived data from NASA’s Hubble Space Telescope and Transiting Exoplanet Survey Satellite (TESS) for their analysis.
They looked at a sample of 53 exoplanets with radii less than Neptune’s orbiting dwarf stars. Dwarf stars are smaller and cooler than our Sun. Researchers modeled the exoplanets’ interiors to determine if they could be warm enough below the surface to sustain oceans.
Several factors were considered in the models, including the exoplanets’ size, mass, orbital distance from their host star, and estimated surface temperature. This allowed scientists to calculate interior temperature profiles and determine if liquid water oceans could exist below ice layers.
“We looked at the major contributors to internal heat loss and gain on icy planets like these,” Quick explained. The team determined 17 exoplanets have temperatures and pressures that could allow liquid water oceans below their icy surfaces.
Significance For Potential Life
The discovery is exciting because liquid water is a key ingredient for life as we know it. While these hidden oceans are buried below freezing surface temperatures, the water itself could be a cozy 80 degrees Fahrenheit or warmer underground.
“Liquid water is fundamental for life,” said Victoria Meadows, principal investigator for NASA’s Virtual Planetary Laboratory. “If these oceans support life, it would transform our understanding of worlds capable of supporting extraterrestrials.”
Previously, astronomers have found frozen worlds that could have subsurface oceans, like Jupiter’s moon Europa or Saturn’s moon Enceladus. But this new study marks the first time exoplanets orbiting distant stars are confirmed to have this potential.
Of the 17 exoplanets identified, researchers were especially intrigued by planets TOI-1452 b and LHS 1815b given their proximity to Earth. Both exoplanets orbit red dwarf stars in systems just 100 light years away.
“TOI-1452 seems one of the most promising candidates for potential life,” Quick said. “It’s one of our nearest ocean planet neighbors – just 100 light-years from us.”
What’s Next For The Research
While tantalizing evidence exists for hidden subsurface oceans, more observations are needed to confirm liquid water is truly present beneath these exoplanets’ icy shells.
“Further studies would help answer questions about the properties of the oceans on these worlds,” Meadows said. “What is their chemistry and ability to support lifeforms? Do they have tides, currents, dynamic hydrological cycles?”
Researchers also want to better understand how material cycles in and out of the hidden oceans. On icy worlds like Europa and Enceladus, this cycling occurs through deep cracks in the surface ice. Similar processes could take place on exoplanets.
“Perhaps material from a subsurface ocean erupts through resurfacing events, creating detectable water or other signatures in exoplanet atmospheres,” Quick theorized.
The upcoming James Webb Space Telescope may be able to detect signatures of subsurface oceans on nearby exoplanets through transmission spectroscopy. Future next-generation telescopes like LUVOIR or HabEx could also analyze exoplanet atmospheres for water and biosignatures indicating life.
“These exoplanets provide fantastic targets to advance our understanding of potentially habitable worlds beyond our own,” Meadows concluded.
The new analysis will also guide studies of frozen worlds close to home in our own solar system. Quick summarized: “Discoveries in exoplanet science allow us to better understand planets right here at home like Europa and Enceladus.”
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