A green comet named Nishimura has recently survived its close encounter with the sun and is now heading towards the outer regions of the solar system. This comet, also known as C/2023 P1, was discovered by amateur astronomer Hideo Nishimura on August 12. It has a green glow caused by high levels of dicarbon in its coma, which is the cloud of gas and dust surrounding its solid core.
Initially, it was thought that comet Nishimura could be a potential interstellar object, like ‘Oumuamua or comet 2I/Borisov, making its first and last trip through the solar system. However, additional observations revealed that it has an extremely elliptical orbit, taking it inside the solar system every 430 years before using the gravity of the sun to return to the Oort Cloud.
Comet Nishimura reached its closest approach to Earth on September 12, passing by 78 million miles from the planet. It reached perihelion, the closest point to the sun, on September 17, coming within 20.5 million miles of our star. Despite the potential dangers of getting so close to the sun, Nishimura seems to have survived mostly unharmed. It is now moving away from the sun and slightly towards Earth, which will make it brighter as more light is reflected in its coma.
However, observing the comet is not an easy task. It is only visible near the horizon shortly before sunrise or shortly after sunset. Additionally, it is now much fainter than when it approached Earth, so a powerful telescope or specialized astrophotography equipment is needed to get a good view of it. Astrophotographer Petr Horalek managed to capture a blurry image of the comet on September 17, but couldn’t see it without his equipment.
Australians may have a slight better chance of seeing the comet in the upcoming week as it will set about an hour after the sun during that period, making it brighter for observers in that part of the world. There is also a possibility that comet Nishimura could be the source of the annual Sigma-Hydrids meteor shower, which could make this year’s shower more active and visually impressive than usual. Additional observations in December could confirm or refute this theory.