Courtesy of Miguel Claro (@miguel_claro)

February 1, 2023

Green Comet C/2022 E3 Visible To Naked Eye This Week, Says Astronomy Professor

Print More

On Feb. 4, green comet C/2022 E3 will become visible to the naked eye under clear skies.

Comets like C/2022 E3 are assigned a numerical and alphabetical value through a series of standardizations.

C/2022 E3 translates to the third of its type comet, neither periodic or dead, that was founded in the first half of March 2022. The first alphabet C signifies its status as neither a periodical comet, recurring in appearance every so often, nor a dead comet, breaking up into pieces. The first set of numbers signifies the year in which it was discovered. The next alphabet E signifies the time of year it was founded. Since there are 52 weeks a year and 26 alphabets, every two week period is categorized by a different letter. The last number represents the order in which this comet type of comet was discovered.

This comet originates farther away from Earth than other comets and only comes around a handful of times, unlike periodic comets that pass by more frequently.

“These comets come from orbits way beyond the orbits of Neptune in a region that’s referred to as the Oort cloud,” said Prof. Philip Nicholson, astronomy. “Every now and then one of these things gets a little gravitational tug or perturbation from a passing star or a large molecular cloud, for example, a gas cloud that the sun travels near and that perturbs the orbit enough that the comet comes into the inner solar system and that’s when we see it…when the tail develops.”

The green coloration of C/2022 E3, distinguishing it from previous comets, is attributed to C₂ molecules — two carbon atoms bonded together — as well as cyanagin, a combination of carbon and nitrogen atoms.

Although C₂ and cyanagin are not uncommon to find in most comets, they are normally not the primary substance to make up comets. Because C/2022 E3 is primarily made of these two molecules, they emit a greater than average amount of green coloration when excited.

However, the brightness of the coloration depends on its proximity to the Sun and Earth. “Generally speaking, [comets] get brighter as they get closer to the Sun because they get warmer then and more stuff evaporates but individual comets deviate in that way,” Prof. Nicholson said. “There’s also a tradeoff: it’s fading intrinsically because it’s moving further away from the Sun [as it moves closer to the Earth].”

Nicholson also noted that the full moon, set to rise on Feb. 5, will decrease the quality of viewing for spectators because the extra brightness will make the comet harder to see. Therefore, the optimal time to view C/2022 E3 is in the few hours before sunrise for the next couple of nights since the comet will be closest to the Earth on Feb. 1.

In addition to regular opening hours on Friday nights, the Fuertes Observatory will be open on Wed., Feb 1 at 7:30 p.m. for viewing of the green comet C/2022 E3.