Green comet will expand knowledge of the Solar System

Adda Avendaño

In March 2022, the Astronomical Center Zwicky Transient Facility (ZTF), which conducts systematic searches for short-lived transient astronomical phenomena, captured an image of a comet approaching the Earth from the far reaches of the Solar System that could probably be observed with the naked eye between late January and early February 2023.

Once it was located, and to determine the purpose of determining that C/2022 E3 (ZTF), as the celestial body was the celestial body, did not pose a risk to the Earth, the experts began to track it with daily images and, using mathematical models, located mathematical models, they located it's probable its probable origin and the trajectory it would follow around the Sun.

A Journey of 50 thousand years

The head of operations of the "Luis Enrique Erro" Planetarium (PLEE) of the Instituto Politécnico Nacional (IPN), Juan Antonio Juárez Jiménez, explained that there are "short period" comets that come from the Kuiper Belt, a zone located beyond the orbit of Neptune, which contains millions of icy bodies and where the dwarf planet Pluto is located.

He added that there are other comets called "long period", which come from a place even farther away than the Kuiper Belt, at the limits of the Solar System, called the Oort Cloud, where abundant remains of the formation of the Solar System are found.

The Green Comet

Comets are bodies of dirty ice (ice of ammonia, methane, and other elements), which contain many incrustations trapped in their structure, and when they orbit around the Sun, by the action of heat, the surface of their nucleus sublimates, that is, it passes directly from the solid to the gaseous state. The sublimation originates a kind of cloud of gas and dust around it, which is called "coma", and at least a couple of tails.

One of the tails is long and faint, formed by the gas and dust released in its movement around the Sun, and the other is called an ionic tail because it is formed by electrically charged materials, this one is generally brighter and always shows in the opposite direction to the Sun, due to the action of the solar wind.

This was explained by Wilder Chicana Nuncebay, member of the Astronomy and Space Sciences area of PLEE, who added that the presence of a particular color, caused by exposure to solar radiation, shows the abundance of a certain element, in this case, the green color indicates the existence of diatomic carbon (C_2) in its external part.

If C/2022 E3 (ZTF) is a long-period comet, it is possible that it passed by the Earth 50 thousand years ago, when the Neanderthals inhabited the planet, in the Upper Paleolithic, or it was attracted by the Sun's gravitational force from the region of the Heliopause, a kind of bubble that marks the border of the Sun's atmosphere with the interstellar medium, the farthest place in the Solar System.

"The place where this comet comes from makes it ideal for studying the composition and characteristics of a region that preserves the remains of the origin of the Solar System, hence its importance for astrophysics," Juárez Jiménez emphasized.

"In its interior, there may be other elements, but since we cannot access them directly, it will be of great interest to study the chemical composition of the material released by exposure to the Sun's radiation, employing spectroscopy, when the comet is in the vicinity of the Sun", indicated the Master of Science.

About its denomination, he clarified that, according to the Comet Nomenclature System, approved by the International Astronomical Union (IAU), the prefix indicates the nature of the comet: P for periodic and C for non-periodic; then the year of its discovery (2022 in this case) is placed, followed by a letter, according to the fortnight of the month in which it was discovered: A= first fortnight of January, B= second fortnight of January, C= first fortnight of February, D= second fortnight of February, E= first fortnight of March and so on.

The number 3 refers to the fact that it was the third comet to be discovered and the initials ZTF correspond to the telescopes of the Zwick Transient Facility. In this context, another of the unknowns that will be discussed now that it has already passed in front of the Earth is whether its orbit is closed, whether it happened during the time of the Neanderthals during the Upper Paleolithic, or whether it is a non-periodic comet whose trajectory will take it out of the Solar System never to return.

Was it Visible?

Once comet C/2022 E3 (ZTF) reached its closest approach to Earth (perigee), at about 42 million kilometers, less than a third of the distance to the Sun, on February 1, it was visible to the naked eye in very dark areas throughout the night and before dawn.

Regular observers searched the sky for the North Star, which belongs to Ursa Minor, and using it as a reference, they focused on the constellation Giraffe where they were able to locate the comet. Many of them did not need any type of astronomical instrument to see the small green speck in the sky, many others used binoculars or small telescopes to magnify the star several times, but without losing details, and a large part of the population could not see it because of the light pollution where they were.

"Although astronomical observation is very beautiful, it requires a lot of patience. You have to wait for the sky to clear at some point, either at dusk or in the early morning, to be able to locate the celestial objects and follow their movement", explained Wilder Chicana.

The PLEE experts agreed that the passage of this comet should not provoke any fear based on superstitions or beliefs without scientific basis, since it was an astronomical phenomenon and, in this case, a unique event that we were fortunate to witness and enjoy at this historic moment. ASTRONOMIC Unit

It is the distance that exists between the Earth and the Sun and is equivalent to 150 million kilometers. The C/2022 E3 (ZTF) came from the Heliopause, is the boundary between the Sun's atmosphere and the interstellar medium whose distance is one thousand astronomical units.