Comet C/2022 E3 (ZTF) is approaching Earth and has already passed the limit of naked-eye visibility. It can now be seen well with small telescopes and conventional triaxes, and early observers report visibility without instruments. The comet has been visible all night since mid-January and should reach its peak brightness in late January and early February. However, when it comes to naked-eye viewing, astronomers are tempering their hopes.
Comet C/2022 E3 (ZTF), nicknamed the “Neanderthal Comet” by the media because its last return to the Sun and Earth was about 47,500 years ago, is approaching Earth and continuing to brighten.
“The period of best visibility is therefore still ahead of us,” Martin Mašek of the Czech Astronomical Society pointed out, adding that astronomers are nonetheless dampening their enthusiasm for the “bright comet flying through the sky.”
“It won’t be a very bright comet, like comet C/2020 F3 (NEOWISE) was in 2020, but already several experienced observers are reporting the visibility of the comet with the naked eye under dark skies far from cities, on the night of Tuesday, January 24, for example, from Kozákov,” he added.
Some observers were also supposed to have seen it with the naked eye last week. However, according to astronomers’ statements to the News, the sighting was made under the most ideal conditions and suitable weather. They were also said to be “sharp-eyed individuals.”
The comet’s two tails are depicted in the first image: a long, ionized tail and a bright, dusty tail. The dusty tail of comet ZTF is curving away from us due to its position relative to the Earth and the Sun. This gives us an increasingly unusual view of the comet. Also striking is the green color of the comet’s head, caused by sublimating cyanide in the comet’s head (coma).
Its closest approach to us will be on February 1. This is not the first time this comet has passed the sun. Before its current entry into the inner parts of the Solar System, it was on a strongly elongated elliptical orbit for about 47 500 years. It had at least one consecutive orbit around the Sun.
C/2022 E3 will pass through occultation (the closest point in its orbit to the Sun) on January 12, 2023, at a distance of 166.3 million kilometers from the Sun. It will be closest to Earth on February 1, 2023, coming within 42.5 million km of our planet). “Thus, its highest brightness is expected in late January and early February,” Mašek said.
At the same time, it should reach its maximum brightness, around 5 mags. In the sky outside the city, experienced observers could easily see it with the naked eye as a tiny, hazy star.
The comet is now visible with conventional triaxes and small telescopes. At the same time, in perfect viewing conditions – outside cities and under very dark skies – the first people are reporting its visibility with their eyes. Its motion across the sky slowly accelerates as it gets closer to Earth. The comet has already entered the so-called circumpolar region of the sky, i.e., it does not fall below the horizon and can be seen all night.
On January 21, it passed into the constellation of the Dragon; on Wednesday, January 25, it will enter the Little Bear; on January 30, it will pass just 10 degrees from Polaris. According to astronomer Pavel Suchan, we will see it in the region between the Big Dipper and the Little Dipper.
The first day of February will be the closest, but from February 2 onwards, the moon will start to interfere strongly, as the full moon will have already set in on February 5. Moonless skies await the comet again on February 8, when it will move through the constellation of the Wagon. On February 9, it will enter the constellation Taurus. In Taurus, high in the winter sky, we will see the comet near the bright planet Mars on February 11 and 12.
By then, its brightness will have dropped below naked-eye visibility, but it will be readily observable in trituration until the end of February. It will be visible in small telescopes (with a diameter of 7 cm) until the end of March when it will be very low on the horizon in the constellation Eridanus.
It will not return
After passing through the inner parts of the Solar System, the gravitational pull of the giant planets will turn the comet’s orbit into a hyperbola, leaving the Solar System forever.
“Yes, it won’t come back,” Suchan confirmed despite earlier reports. “This is the last chance to see it.”