A team led by the Southwest Research Institute found evidence of hydrothermal or metamorphic activity on the icy dwarf planets Eris and Makemake, located in the Kuiper Belt. Methane found on their surfaces shows signs of hot or even hot geochemistry in their rocky cores; This is quite different from the methane in the comet.

Dr. SwRI, an expert in planetary geochemistry and lead author of a paper on the discovery. “We’re seeing some interesting signs of warm times in cold places,” Christopher Glein said.

“I came to this project thinking that large Kuiper Belt Objects (KBOs) must have ancient surfaces filled with materials inherited from the primordial solar nebula, since their cold surfaces can store volatiles such as methane. Instead, the James Webb Space Telescope (JWST) has discovered that thermal processes in Eris and we found evidence of methane production from Makemake.”

The Kuiper Belt is a large region of donut-shaped icy bodies orbiting Neptune at the edge of the Solar System. Eris and Makemake are comparable in size to Pluto and its moon Charon. These objects probably formed early in the history of our solar system, about 4.5 billion years ago. Far from the warmth of our sun, KBOs were thought to be cold, dead objects.

A recently published paper from the JWST survey made the first observations of isotopic molecules on the surfaces of Eris and Makemake. These so-called isotopologues are molecules containing atoms with different numbers of neutrons. They provide useful data for understanding the evolution of the planet.

The JWST team measured the composition of the dwarf planets’ surfaces, including the ratio of deuterium (heavy hydrogen, D) to hydrogen (H) in methane. Deuterium is thought to have been formed in the Big Bang, and hydrogen is the most common nucleus in the universe. The D/H ratio in a planetary body provides information about the origin, geological history, and formation pathways of hydrogen-containing compounds.

“The moderate D/H ratio we observed with JWST argues against the presence of primitive methane at the ancient surface. Primordial methane would have had a much higher D/H ratio,” Glein said.

“Instead, the D/H ratio indicates the geochemical origin of the methane produced at depth. The D/H ratio is like a window. In a sense, we can use it to peer into the depths. Our data points to high temperatures at which methane could be cooked in the rocky cores of these worlds. Molecular nitrogen (N) ₂ ) can also be produced and we see this in Eris as well. “Hot cores may also indicate potential sources of liquid water beneath their icy surfaces.”

Over the past two decades, scientists have learned that icy worlds may have undergone much more internal evolution than previously thought. Evidence of subsurface oceans has been found on several icy moons, such as Saturn’s moon Enceladus and Jupiter’s moon Europa. Liquid water is one of the most important components that determine the potential habitability of a planet.

The possibility of water oceans on Eris and Makemake is something scientists will study in the coming years. If any of these were habitable, this would be the farthest world in the solar system that could harbor life. The search for chemical indicators of internal processes takes a step in this direction.

“If Eris and Makemake contained or may still contain hot or even hot geochemistry in their rocky cores, cryovolcanic processes are likely to have released methane onto the surface of these planets in geologically recent times,” said Dr Will Grundy. The astronomer at the Lowell Observatory is one of Glenn’s co-authors and the lead author of the accompanying paper.

“We found a carbon isotope ratio (13 C/2C) that indicates relatively recent surface renewal.”

This work is part of a paradigm shift in planetary science. It is increasingly recognized that cold, icy worlds can be warm to the soul. Models developed for this study also show the formation of geothermal gases on Saturn’s methane-rich moon Titan. Additionally, the unexpected finding of activity at Eris and Makemake highlights the importance of internal processes in shaping what we see in large KBOs and is consistent with findings at Pluto.

“Following New Horizons’ flyby of the Pluto system and with this discovery, the Kuiper belt appears to be much more vibrant in terms of hosting dynamic worlds than we could have imagined,” Glein said. “It is not too early to start thinking about sending a spacecraft to fly past another of these objects to put the JWST data into geological context. I believe we will be amazed at the wonders that await us.”