A green comet named Nishimura recently survived its close encounter with the sun and is now heading toward the outer regions of the solar system. This comet, also known as C/2023 P1, was discovered on August 12 by amateur astronomer Hideo Nishimura. It has a green glow caused by the high dicarbon content in its coma, the cloud of gas and dust surrounding its solid core.
It was originally thought that Comet Nishimura could be a potential interstellar object like Oumuamua or Comet 2I/Borisov, making its first and last journey through the solar system. However, additional observations revealed that it has an extremely elliptical orbit that takes it deep into the solar system every 430 years before using the Sun’s gravity to return to the Oort Cloud.
Comet Nishimura made its closest approach to Earth on September 12, when it passed at a distance of 78 million miles. On September 17, it reached perihelion, the closest point to the Sun, and came within 20.5 million miles of our star. Despite the potential dangers of getting so close to the sun, Nishimura appears to have survived the journey largely unscathed. It is now moving away from the Sun and slightly toward Earth, becoming brighter as more light is reflected from its coma.
However, seeing the comet is not an easy task. It is only visible near the horizon just before sunrise or just after sunset. Additionally, it is now much fainter than when it approached Earth, so you’ll need a powerful telescope or specialized astrophotography equipment to get a good look at it. Astrophotographer Petr Horalek managed to capture a blurry image of the comet on September 17, but without his equipment he was unable to see it.
Australians may have a slightly better chance of seeing the comet next week, as it will set about an hour behind the Sun during that period and will therefore be brighter for observers in that part of the world. There is also the possibility that Comet Nishimura is the source of the annual Sigma Hydride meteor shower, which could make this year’s shower more active and visually impressive than usual. Further observations in December could confirm or refute this theory.