When it passed by Earth in mid-2018, comet 46P/Wirtanen released an unusually high amount of alcohol.
According to Neil Dello Russo, a comet scientist at Johns Hopkins University, 46P/Wirtanen has the highest concentration of alcohol on aldehyde ever measured on comets. This provides insights into how carbon, oxygen, and hydrogen molecules were distributed in the primordial Solar System where Wirtanen was formed.
46P/Wirtanen during its flyby of Earth in late 2018. (Photo: NASA).
46P/Wirtanen is a frequent visitor to the Solar System. It orbits the Sun every 5.4 years. At times, it comes close enough to Earth to be visible to the naked eye in the night sky.
Comets differ from asteroids in that they are composed of carbonic methane, frozen water mixed with large molecular weight organic compounds, and other minerals. As a comet approaches the Sun, its rocky particles begin to sublimate, creating the comet’s head—a massive glowing cloud of gas and dust surrounding the comet’s nucleus. Simultaneously, solar radiation pushes the comet’s head away, forming the comet’s tail.
However, in the case of 46P/Wirtanen, studies have discovered some mysterious mechanisms that also cause this comet to heat up.
- The first hypothesis is that solar radiation may have ionized some molecules near the comet’s nucleus, releasing high-energy electrons. These electrons could collide with other molecules and transfer energy in the form of heat.
- The second hypothesis suggests that solid chunks and ice particles breaking off from the comet fall away from the nucleus before sublimating and releasing energy.
Other components essential for life have also been found on 46P/Wirtanen. Thus, “these dirty snowballs” could be extremely important not only for our existence but also for life elsewhere in the universe.
“Studies of comets like this are fascinating because they serve as a launchpad to answer the question—are we alone?”, said astronomer Greg Doppmann from the Keck Observatory.
