Comet “C/2022 E3 (ZTF)” will cross Earth’s sky again 50,000 years after its last visit and will be visible to the naked eye at the end of January.
The small rocky and icy body is only a kilometer in diameter. The comet was discovered in March 2022 by the Zwicky Transient Facility (ZTF) program, which operates the Samuel-Oschin Telescope at the Palomar Observatory in California.
50,000 years ago, “C/2022 E3 (ZTF)” visited the inner solar system and passed close to Earth. It has been detected again in the path of Jupiter’s orbit and will pass close to the Sun this week.
Astronomers, who have calculated its trajectory after months of observations, have stressed that it will reach its perihelion – the closest point to the Sun – on January 12.
As a comet approaches the Sun, the ice in its nucleus turns into a gaseous state and releases a long tail that reflects light from the star.
This luminous phenomenon is what will be seen from Earth, initially in the Northern Hemisphere, as “C/2022 E3 (ZTF)” approaches.
The comet will shine in all its glory “when it is closest to Earth,” says California Institute of Technology physics professor Thomas Prince, who works for the ZTF.
However, it will be less spectacular than Comet Hale-Bopp (1997) or Comet Neowise (2020), which were much larger.
The space object can be seen at night with a good pair of glasses or even with the naked eye, provided the sky is clear, there is no light pollution and the brightness of the Moon is not disturbing.
“Maybe we’re lucky and it’s twice as bright as expected,” ventures the astrophysicist of the Paris-PSL Observatory, Nicolas Biver.
The best observation period will be the weekend of 21 and 22 January and the following week.
During this time it will pass between the constellations Ursa Minor and Ursa Major. Later it can be seen in the southern hemisphere and then departed towards the limits of the solar system, where it was probably born.
According to current models, comets come either from the Kuiper belt, located beyond the orbit of Neptune, or from the Oort cloud, an immense area located almost a light-year from the Sun, at the limit of its gravitational field.
This comet “originates initially from the Oort cloud,” according to Biver considering its orbit.
This time, it will likely “be out of the solar system forever,” says Biver.
Preparations to see it will be complete, and scientists hope to learn a little more about the composition of comets, thanks in particular to the powerful James Webb Space Telescope.
“We will observe from all sides. It is not the comet of the century, but we are happy to be able to observe comets like this every one or two years, as we consider them traces of the formation of the solar system” , explains the astrophysicist.
