Hopesโ Dimโฃ for Habitable ‘Hycean‘ Planets โFollowing New Simulations
WASHINGTON – Recent simulations challenge the prevailing theory that “Hycean” planets – potentially habitable worlds covered in vast oceans -โค are common throughout theโ galaxy,โ casting doubtโข on the likelihood of finding life on exoplanets like K2-18b. Theโฃ findings, published by researchers led by Dr. Chao Dorn at the University of Arizona, suggestโ these sub-Neptune planets are more likely to possess thickโค atmospheresโข and limited surface water, diminishing โtheir potential for supporting life as we know it.
Just months ago, K2-18b, โlocated 124 light-years away, generated excitement after the โdetection of dimethyl โขsulfide (DMS), a potential โbiomarker โfrequently enough associated with life on Earth. Thisโ sparked speculation about a global ocean โฃsurroundings. however, subsequent analysis revealed the DMS evidence โคwas weak, and the new research โindicates that K2-18b,โ and planets like it, โฃmay not be the water worlds initially envisioned.
The team modeled the earlyโข evolution of 248 sub-Neptune planets, factoring in interactions โbetween magma and atmosphereโ -โ elements frequently enough overlooked in previous studies.โฃ The results demonstrate โthatโ none โof the simulated planetsโข developed the massive water layers โpreviously hypothesized. Planets โฃwith 10-90% โwater content, characteristic of the Hycean model, were not observed. Instead, hydrogen and oxygen tend toโ bind with metals โขand silicates within the planet’s interior,โฃ effectively โtrapping water deep below the surface.โข Even โคplanets initially โคrich in โice retained less than 1.5% of their โmass as surface water.
“Water that reallyโฃ survives โon โthe surface isโฃ only a few โคpercent,” โขexplained Aaronโ Werlen, โฃa researcher and colleague of โDr. Dorn.
Interestingly, the simulations revealed that planets forming closer to their stars -โ not beyond the “snow line” โขwhere ice canโฃ condenseโข -โ are moreโ likelyโข to develop water-rich atmospheres, formed through chemical โขreactionsโค between hydrogen and oxygen from molten rock.
The implications โfor astrobiology are significant. If hycean planets are rare, the search for extraterrestrial life may need to refocus on smaller, โฃrocky planets similar to earth. Despite these findings, K2-18bโ remains a valuable subject of study as a representative of the โขcommon sub-Neptune โฃplanet โtype, offering insights into planetary system โformation.
“The earth may not be โas famous as what weโ imagine,” โขDr. โDorn stated. “In our simulation, he โisโข seen as a fairly ordinary โขplanet.”