Monday, February 6, 2023 | 10:15 a.m.
Although it has been visiting us since February 1, the green comet, a space body that visits us every 50,000 years, will only be visible to Argentines and all those who live in the Southern Hemisphere tonight.
This is comet C/2022 E3 (ZTF), the name that astronomers gave to this ball of space ice after the Zwicky Transient Facility telescope discovered it in March last year.
“The so-called green comet reached its closest approach to planet Earth. This star takes 50,000 years to complete a complete orbit around the Sun”, explained to Infobae the astrophysicist and researcher at the National Council for Scientific and Technical Research of Argentina (Conicet), Beatriz García.
The expert clarified that this space phenomenon could already be observed since February 1 in the Northern Hemisphere. But only now can it be seen in these latitudes. “You have to observe it towards the north in the constellation of Auriga during the night, at around 10 pm. However, the crescent Moon can interfere with its observation”, indicated the researcher, who added that the passage of the comet has “no effect on the Earth or on the Solar System” and specified that “they are small and interesting objects that call the attention if they can be seen with the naked eye.
According to NASA, if the comet continues with its current footprint of brightness, it can be observed with the help of binoculars and with the naked eye for the human eye in skies with no light pollution.
“The comet of the moment was discovered almost a year ago by the Zwicky Transient Facility (ZTF), a program for observing short-term astronomical phenomena (from novae and supernovae to transits of asteroids and comets in front of stars), belonging to to the Palomar Observatory, in San Diego, California, United States. It was there where, with the help of the Samuel Oschin Telescope (1.2 meters in diameter), on March 2, 2022, astronomers Frank Masci and Bryce Bolin discovered the object that today captures our attention and expectations,” explained the graduate. Mariano Ribas, in charge of the area of astronomical dissemination of the Planetarium of the City of Buenos Aires “Galileo Galilei”.
And he added: “At that time, the ZTF comet (as it was baptized from the aforementioned scientific program) was 640 million km from the Sun, that is, quite “inside” the orbit of Jupiter. And it was extremely low-bright: a meager magnitude 17. Over the weeks, scientists determined that C/2022 E3 (as its formal catalog entry) had an immense orbit around the Sun: 50,000 years. And also, very eccentric (extremely “oval”) and inclined with respect to the orbital plane of the Earth (109°). A colossal gravitational course, typical of the so-called “non-periodic comets”: the prefix C/, precisely, indicates that it is an object of this class (unlike “periodic comets”, those with orbits of up to 200 years, that carry the P in their name, such as 1P/Halley or 10P/Tempel)”.
The comet in the Argentine sky
“In our country, and because of its orbital trajectory, C/2022 E3 would only begin to be seen from February 5 (in the northern provinces, perhaps a day before), between 9:00 p.m. and 11:00 p.m. , and a few degrees above the northern horizon. By then, it will be located slightly “to the left and below” of the famous Capella star: the sixth brightest in the night sky. An excellent reference. From that date, day after day, the comet will gain altitude. Always at the same time, and in the same area of the sky, as shown by the 2 celestial maps that we have specially prepared, which account for their position in relation to stars and constellations in that area of the firmament,” said the expert from the Planetary.
And he added that between February 5 and 8 the constellation of Auriga will transit. This last day, around 9:00 p.m., the ZTF will be located at a more comfortable 20 to 22° above the horizon of Buenos Aires and its surroundings (in other areas of the country there will be small differences in time and height).
“Starting on February 9, the comet will parade through the constellation of Taurus, where, among other things, it will have an apparent encounter with Mars, on the 10th and 11th. Another excellent reference to locate the comet. To understand it better, it must be taken into account that, as we have already said, the comet had its closest approach to Earth on February 1. And that, from that moment, it will move away, and lose its shine. It is also true that, as it gains height above our northern horizon, it will “escape” from the “worst” area of the firmament: the one with the highest atmospheric absorption and light pollution. For this reason, the days that -in principle- would give us the best “cost/benefit” between both factors, will be from the 8th to the 12th. Or perhaps, until the 14th or 15th, when it will be located near the bright, reddish and famous star Aldebarán”, concluded Ribas.
The particularity of this phenomenon is its color and the fact that it is a comet with long periods, which are those that take more than 200 years to orbit the sun.
Comets are a kind of cosmic snowball, with ice, frozen gases, dust, and rocks, ranging from a few kilometers in diameter to hundreds of kilometers. The green color, in this particular comet, is due to its molecular composition that contains dicarbos and cyanogen, both chemical components that appear green when exposed to sunlight.
4 tips to observe the phenomenon from Argentina:
-The comet will pass close to Earth between February 1 and 5. The closest point will reach it on February 2, standing at around 43 million kilometers from it.
-You have to observe the night sky in the hours before dawn, they explained from NASA.
-There are two applications that can be very useful for observing the sky: Night Sky and Sky Map.
-The green color is due to the cyanogen gas and diatomic carbon contained in its nucleus and which, when released and interact with sunlight, give it that striking appearance.
