Space, the green comet over the weekend: it will return in 437 years

Comet Nishimura, discovered just a month ago by the Japanese amateur astronomer Hideo Nishimura, will be visible over the weekend with simple binoculars or even with the naked eye. However, it will be necessary to be in a very dark, starry and light pollution-free environment. It is a rocky and frozen body, the exact dimensions of which are not yet known, observed for the first time on 11 August. (TRACES OF WATER ON A RARE COMET)

The green comet

C/2023 P1 is the code name of the star that will reach the minimum distance from the earth (125 million kilometres) on 12 September, set in the constellation Leo. The minimum distance from the Sun (43 million kilometres), the perihelion, will instead be reached on 17 September in the constellation Virgo. Maximum visibility should be guaranteed right next weekend, between Saturday 9 and Sunday 10 September, before dawn, the experts explain. “It has a long-period orbit with a last pass close to the Sun that dates back to 437 years ago,” explained Nicolas Biver, a CNRS researcher at the Paris Observatory-PSL. While no trace of this icy visitor’s last passage has been found in the astronomical archives, the astrophysicist said. When comets (celestial bodies from cold regions of the solar system) approach the sun, the ice contained in their nucleus sublimates and releases a long trail of dust that reflects the light. And it is precisely these “shiny hairs” that can be observed from the Earth. Nishimura’s ‘hair’, unlike other comets, is green because this celestial element contains more gas than dust. “The best thing is to look at the sky before dawn (around 6 in France, and therefore also in Italy), towards the north-east, to the left of Venus (commonly called the Shepherd’s Star), in a clear sky without pollution, advised the researcher.