Triton Fosters Rare Icy Union between Carbon Monoxide and Nitrogen

An international team of scientists used the Immersion Grating Infrared Spectrometer (IGRINS) to discover an icy mixture of two common molecules (N₂ and CO) on Triton.

Neptune is the farthest known planet of our solar system and that’s the reason why we have minimal information about this ice giant. Thanks to the technological advancement in recent past, space agencies are now trying to explore Neptune and its moons in an attempt to find some useful information about the origin of life.

Recently, a team of researchers managed to observe an extraordinary phenomenon on Triton, the largest moon of Neptune. They found that a very specific wavelength of infrared light was absorbed while they were viewing the moon by using the Gemini South Telescope in Chile. The interesting thing about the observation was that this wavelength is absorbed only when molecules of Carbon Monoxide and Nitrogen combine with each other. Consequently, the researching team deduced that Triton hosts a rare icy union on its surface.  

Triton

It is the only large moon of our solar system that orbits in the opposite direction of the rotation of its planet. This strange motion strengthens the theory that Triton is actually a captured object from the Kuiper Belt which was pulled by the strong gravitational attraction of Neptune, in the early days of our solar system. It also explains the similarities between Triton and Pluto, a dwarf planet in the Kuiper Belt. The surface temperatures of these celestial bodies are so close to the Absolute Zero that everything freezes into ice.

The terrain of Triton can be divided into two categories. The first one of them is formed by water and is largely composed of Carbon Dioxide ices while the other one is dominated by different types of volatile ices. Similarly, the atmosphere of Triton is composed of Nitrogen, Carbon Monoxide, and Methane and is 70,000 times less dense than the atmosphere of our planet.

Uncommon Pairing of Common Molecules

The international team of astronomers was led by Stephen C. Tegler, a Researcher at the Astrophysical Materials Laboratory of the Northern Arizona University. They used the Gemini Observatory and IGRINS, a high-resolution spectrograph, to observe the unique infrared signature on Triton. Both these technologies are funded by the National Science Foundation (NSF) and the Korea Astronomy and Space Science Institute (KASI). Tegler referred to the significance of this discovery by saying,

“While the icy spectral fingerprint we uncovered was entirely reasonable, especially as this combination of ices can be created in the lab, pinpointing this specific wavelength of infrared light on another world is unprecedented.”

This finding is quite important for scientists because it offers useful insights about the triggering of seasonal atmospheric changes and the transportation of materials across the surface of Triton (through geysers).

First Observation of Geysers on Triton

The first observation of these iconic geysers was performed by Voyager 2 spacecraft in 1989. Since then, a number of theories have emerged about these geysers but all of them lack scientific evidence to support the claims. For instance, some researchers believe that an internal ocean on Triton was the source of the erupted material. Contrary to that, others believe that the heating of a thin layer of volatile ice, during summer, initiated these geysers. The icy union detected in the latest research can have a possible connection with them as the images of Voyager 2 shows dark streaks on the surface of the distant moon. Henry Roe, a member of the researching team who is currently serving as the Deputy Director of Gemini, acknowledged that in the following words:

“Despite Triton’s distance from the Sun and the cold temperatures, the weak sunlight is enough to drive strong seasonal changes on Triton’s surface and atmosphere. This work demonstrates the power of combining laboratory studies with telescope observations to understand complex planetary processes in alien environments so different from what we encounter every day here on Earth.”

Future Prospects

Neptune takes around 165 Earth-years to complete an orbit around the sun which means that a season on Triton can last for around 40 years. Given the fact that the moon began its current summer season in 2000, we still have 20 more years at our disposal to solve this mystery. Researchers believe that the mixture of Carbon Monoxide and Nitrogen ices is quite common in that part of the solar system and even Pluto experiences this rare union. They are hopeful that the New Horizons spacecraft will unveil a lot of these secrets in the coming years.