A comet that occurs once every 50,000 years will visit the Earth. How are comets named?

China Science and Technology News, January 9 (Xu Qiqi)

According to Xinhua News Agency, astronomers recently said that a newly discovered comet will fly past the Earth in the next few weeks, the first time it has been seen in 50,000 years. The comet is numbered C/2022 E3 and was first observed by the Zwicky Transient Research Facility in March 2022. It will pass the perihelion on January 12 and the perigee on February 1. If the observation conditions are good, it may be clearly visible to the naked eye.

A comet is what some Chinese stories call a "broom star". It is a celestial body that orbits the sun and whose brightness and shape change with the distance from the sun when it enters the solar system. A comet consists of three parts: a nucleus, a coma, and a tail. The nucleus is the solid part at the center of the comet, which is made of ice, rocks, dust, etc. The coma is the evaporated product of the nucleus. Usually, the closer to the sun, the brighter and larger the coma is. The tail is the extension of the tail of the comet, which is divided into two types: a dust tail and an ion tail.

How are comets named?

Generally, comets are named after the surnames of their discoverers, and a comet can only be named after three discoverers at most. In addition, the International Astronomical Union also refers to the naming rules for asteroids and uses numbers as the names of comets.

The first letters of the numbers mean: A/ may be an asteroid; P/ confirmed to be a short-period comet (a comet with a period shorter than 200 years). When it returns again, the periodic comet catalog number will be added in front of P/; X/ a comet whose orbital elements have not yet been calculated; C/ a long-period comet (a period longer than 200 years) or a non-periodic comet; D/ a comet that no longer returns or may have disappeared. If a comet splits into two or more nuclei, -A, -B, etc. will be added to the end of the number to distinguish them.

The letters and numbers at the end indicate the time when the comet was discovered. The comets are numbered in sequence using the 24 capital letters excluding I and Z, with E representing the first half of March. The numbers 1, 2, 3, etc. are used to indicate the order of the comets discovered in the same half month.