Comet Nishimura, the beautiful comet almost no one saw

Beautiful Comet Nishimura

Comet C/2023 P1 (Nishimura) burst into our consciousness in August of 2023. By all accounts, we could expect it to get bright! But, as often happens with comets, this one didn’t get as bright as expected. Indeed, astrophotographers caught glorious images of it. See some in the video above. But it never became easy to see with the eye, however.

At first, the comet started out as a morning object. Then, it left the morning sky around September 10, 2023 and became an evening object. A few people picked it up in the evening skies, and early reports of the comet in the evening were promising. But … no joy. Now, the comet has made its closest pass to our sun in its 435-year orbit. It will be hanging out by the sun in our sky for the next couple of months, making it impossible for amateurs to view.

Videos of Nishimura

However, professional observatories that peer at the sun have caught the comet in their images. You’ll find some amazing video of the comet by the sun on September 17, toward the end of the video above, or in the tweet below.

Comet Nishimura – that great icy ball moving through space, which so many have captured on film – was closest to Earth on September 12. It was then closest to the sun (perihelion) on September 17.

Meanwhile, the comet is also expected to reappear in our dawn skies toward the end of 2023. But by then it’ll be too distant, and too dim, to view, as it sweeps farther away. But we may get to see some of what it left behind in December, however, with the Sigma Hydrid meteor shower! Read on to learn more about it.

Did the new comet spawn a meteor shower?

On August 30, 2023, astronomers learned that the orbit of newly discovered Comet Nishimura is similar to that of meteors in the annual Sigma-Hydrid shower. Meteors in annual showers are known to be debris left behind by icy comets as they orbit the sun. And – though the Sigma-Hydrid is a minor shower – it is a known shower, active around December 9-12 each year. So, scientists (those strivers to learn the sources of things) will closely monitor these meteors this year!

To be sure, if scientists see elevated activity in the Sigma-Hydrids in December, it’ll help confirm comet Nishimura as the source of the meteor shower.

In addition, if the comet is indeed related to the Sigma-Hydrids, then the comet must be “refilling” its path with icy comet particles. And, in December, when Earth again sweeps near the comet’s path, these same bits of leftover comet debris will produce the meteor display.

The video below is from December 2022, taken in the Caribbean. It’s a Sigma-Hydrid meteor, a possible Nishimura-related meteor!

The story of comet Nishimura

Hideo Nishimura of Kakegawa, Japan, was photographing the night sky on August 11 and 12, 2023, when he captured a new comet that now bears his name: comet C/2023 P1 (Nishimura). In fact, the comet was hiding in the sun’s glare before Nishimura picked it up in his images.

It continued to brighten as it closed in on the sun (perihelion was September 17). Later, after passing closest to Earth on September 12, it emerged low in the evening sky. Some saw it with binoculars in the western evening twilight. Now, it’s too close to the sun for observing, and it will stay that way until it’s far away and too dim to see again.

View at EarthSky Community Photos. | Petr Horalek in Zahradne, Slovakia, made this composite image of new comet Nishimura (left) and Venus, the brightest planet, on September 9, 2023, when the comet was in the morning sky. Thank you, Petr! Now, the comet has moved to the evening sky, and early sightings suggest it has brightened.

A local comet

Moreover, on September 1, 2023, NASA/JPL made new orbital calculations that indicated that comet Nishimura orbits the sun every 435 years, which suggests this is a “local comet” from our solar system and not an interstellar comet.

Closest approach to Earth occurred on September 12, 2023, when the comet passed 78 million miles (125 million km) from Earth.

Perihelion – or closest approach to the sun – was on September 17, 2023, at 27 million miles (43 million km) from our star.

In fact, during perihelion, comet Nishimura passed closer to the sun than Mercury’s orbit.

Path of new comet C/2023 P1 (Nishimura) around the sun. In this chart from Guy Ottewell, the grid lines are 1 AU (1 Earth-sun distance) apart. Stalks on the comet’s path mark 1-month intervals. Red lines connect the comet and Earth, and the comet and the sun, at their closest. Does the path of the comet through space match that of the Sigma-Hydrid meteor shower? Image via Guy Ottewell. Used with permission.
View larger. | Here’s the path of comet Nishimura, largely through the zodiacal constellations. The comet climbed into the sky’s Northern Hemisphere on March 28. It was in conjunction with the sun (behind the sun) on June 15. Then, it ascended northward through the ecliptic plane on August 22. It was farthest north (declination about 24 degrees) on September 4. Image via Guy Ottewell. Used with permission.

Sightings of comet Nishimura

Bottom line: Comet Nishimura is too close to the sun for amateurs to view now, but professional observatories that look at the sun are picking it up!

See photos of comet Nishimura from the EarthSky community




IAU Minor Planet Center

Star Walk

September 27, 2023

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Kelly Kizer Whitt

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