Astronomers from the University of Bern propose that exoplanet LHS 3844b hosts hemispherical tectonic activity, driven by vast temperature differences between its day and night sides. Their peer-reviewed study is published in The Astrophysical Journal Letters.
Discovered in 2018 by NASA's TESS mission, LHS 3844b is an Earth-sized world (1.3 times Earth's radius) orbiting a red dwarf star 49 light-years away in the constellation Indus.
With an orbital period of just 11 hours, the planet is tidally locked, showing only one face to its star—like the Moon to Earth. This results in scorching dayside temperatures around 770°C and frigid nightside conditions below –250°C.
Lead author Tobias Meier, an astronomer at the University of Bern, hypothesized that these extremes could drive internal material flows. His team ran advanced computer simulations, varying material strengths and internal heat sources to test this idea.
The models showed upward material flow on one hemisphere and downward flow on the other, creating a circulation between sides.
Surprisingly, some scenarios reversed the expected pattern—where hotter material should rise. Instead, flows opposed intuition.
“This counterintuitive result stems from temperature-dependent viscosity: cold material is rigid and resists deformation, while hot material becomes more fluid, allowing solid rock to flow inward,” explains co-author Dr. Dan Bower.
Such dynamics could trigger intense volcanism on the upwelling hemisphere, akin to Earth's Hawaiian hotspots or Iceland. Dr. Bower notes: “We could envision one side riddled with volcanoes, the other nearly dormant.”
These insights come from simulations alone. Confirming them would require observations like surface temperature maps showing volcanic outgassing or detection of volcanic gases.
