NASA astronomers used the James Webb Space Telescope to directly analyze the surface of the super-Earth exoplanet LHS 3844 b this month.
This discovery marks a significant milestone in astronomy because it allows scientists to characterize the physical geology of a rocky planet outside the Solar System. Understanding these surfaces helps researchers assess the potential habitability of distant worlds.
Located between 48 [1] and 49 [2] light-years from Earth, the planet orbits a red dwarf star. The telescope's data reveals a dark, airless environment with a mineral composition reminiscent of Mercury. Scientists said that the planet lacks an atmosphere to protect its surface from the harsh environment of its host star.
"It's a dark, airless world that looks like Mercury," NASA scientists said.
The extreme conditions on the planet are driven by its proximity to the red dwarf. The dayside temperature is estimated to be over 2,000 K [3], which is hot enough to melt metal. This heat provides a rare opportunity for astronomers to study the thermal emission, and mineralogy, of a rocky body in deep space.
Dr. Emily Millholland, the lead author of the study, said, "For the first time we have been able to characterize surface features on an exoplanet."
NASA's press office said the planet's extreme heat gives a rare glimpse of rocky planet geology beyond the Solar System. By analyzing how the planet reflects and emits light, the team could determine that the world is a barren, rocky sphere without the gaseous envelope found on Earth or Venus.
“"It's a dark, airless world that looks like Mercury."”
The ability to directly characterize the surface of a super-Earth demonstrates the James Webb Space Telescope's capacity to move beyond detecting planets to analyzing their actual composition. While LHS 3844 b is too hostile for life, the techniques used to identify its airless, mineral-rich surface can now be applied to smaller, cooler rocky planets that may possess atmospheres or liquid water.
