Discovered just a month ago by Japanese amateur astronomer Hideo Nishimura, Comet C/2023 P1 Nishimura may become a naked eye object in the days to come as it marks its passage into the inner solar system. With an orbital period of approximately 437 years, comet Nishimura is considered a long period comet, likely originating from the farthest reaches of our solar system.
Comets are essentially small chunks of rock and ice, left behind from the formation of the solar system. They can be classified into two broad categories – long period and short period comets. Typically, short period comets are those that have an orbital period around the sun of less than 200 years, with the longer period comets surpassing the 200-year mark.
While in the frigid depths of the outer solar system, comets are typically frozen over and extremely hard to spot even with the large telescopes, being only a few kilometres across and extremely far away from Earth. But as they make their way towards the inner solar system on their highly elliptical orbits, comets start to heat up and volatile material on the comet’s surface starts to evaporate, releasing gases and dust in its wake.
This release of material becomes visible as a glowing comet head, with distinct tails, called dust and ion tails, forming as a result of the dislodged material from the comet’s surface.
Comet Nishimura is being closely followed by astronomers as its current trajectory will take it very close to the sun, inside Mercury’s orbit, making it a possible candidate for nucleus breakup
Comets’ tails normally point in slightly different directions. The ion tail, composed of ionised gases released from the comet’s surface, points directly away from the sun, in the path of the solar wind. Conversely, the dust tail is typically released in the wake of the comet and pushed outward by radiation pressure from the sun. As the heavier particles released gradually start to fall in orbit around the sun, under the influence of the sun’s gravity, the dust tail starts to showcase a curved appearance.
Comet Nishimura is being closely followed by astronomers as its current trajectory will take it very close to the sun, inside Mercury’s orbit, making it a possible candidate for nucleus breakup. Indeed, it will reach an expected perihelion distance of just 33.7 million kilometres on September 17. Observing Comet Nishimura will be rather challenging in the coming days as it will be rather close to the sun in our skies, currently being in the Leo constellation, and thus only being visible close to sunset and sunrise.
Josef Borg completed a PhD in astronomy at the Institute of Space Sciences and Astronomy, University of Malta, and is currently a researcher at the Faculty of Health Sciences at the University of Malta. He is also Malta’s representative on the European Astrobiology Network Association (EANA) council.
Sound Bites
• NASA’s Ingenuity helicopter has now carried out over 100 minutes of flight time on Mars. The small craft had landed with the NASA Perseverance rover back in February 2021 in the Jezero Crater. While Perseverance continues on its task to search for possible signs of ancient life in the crater, the aim for Ingenuity was to showcase that aerial exploration close to the Martian surface remains a possibility. It has since carried out a series of past flights, with the latest flight occurring today, September 3. This was its 57th flight on Mars, with a flight time of two minutes and nine seconds, and covering a total of 217 metres.
For more soundbites, listen to Radio Mocha every Saturday at 7.30pm on Radju Malta and the following Monday at 9pm on Radju Malta 2 https://www.fb.com/RadioMochaMalta/.
DID YOU KNOW?
• Comet impacts on Earth in the past are thought to have brought us our oceans! During the Late Heavy Bombardment period, some four billion years ago and early on in the solar system’s formation timeline, Earth (and indeed all the newly formed inner solar system planets) experienced a period of increased number of collisions from asteroids and comets. It is believed that Earth received most of its water during this period, originating from water-rich comets colliding with our planet during this period.
• Comets are normally characterised by extremely elliptical orbits. These orbits bring comets towards the inner solar system for a relatively short period of time, with most of the time of the comet’s orbit spent instead in the colder outer reaches of the solar system.