Comet C/2021 O3 (PanSTARRS) Might Be Visible In 2022

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In 2021, the Pan-STARRS system discovered a comet that might become visible by late April 2022. In today’s article, we gathered everything that is known about the comet so far.


What is the comet C/2021 O3 (PanSTARRS)?

On August 1, 2021, the Minor Planet Center officially reported the new comet discovery. The comet was named C/2021 O3 (PanSTARRS) after the Pan-STARRS telescope that first observed it on July 26, 2021. It is the 1.8-meter diameter telescope located ​​at Haleakala Observatory, Hawaii, US. As we mentioned on our Facebook page, right after the discovery, the comet was temporarily designated “P11ibiE”.

At the moment of its discovery, the comet had a visual magnitude of 20 and was located in the constellation Pegasus. This space object is moving on a highly elongated elliptical orbit and most likely belongs to the long-period comets.

Since February 1, 2022, the comet has been too close to the Sun to be properly observed, so at the moment, there is no data about its current brightness.

Is the comet C/2021 O3 (PanSTARRS) visible?

Even with the help of telescopes, the comet is hardly observable yet. However, if it survives perihelion, the PanSTARRS comet might become a binocular target. C/2021 O3 will reach perihelion on April 21, 2022, lying at the distance of 0.29 AU from the Sun — as close as Mercury. At about the same time, C/2021 O3 will have its maximum visual magnitude of about 7.4. On May 8, 2022, the comet will make the nearest approach to the Earth at 0.6 AU, and its visual magnitude will lower to 10.

C/2021 O3 will favor the Northern Hemisphere, where it is expected to be visible by the first few nights of May 2022. In late April-May, the comet will move across Aries, Taurus, Perseus, and Camelopardalis constellations. On May 2, 2022, observers will have a chance to spot a unique event: the waxing Moon, 0.7 magnitude Mercury, and the comet C/2021 O3 will simultaneously appear near the Pleiades star cluster! All four objects will fit within the field of view of wide-angle binoculars (starting from 11° field of view).

Will the comet C/2021 O3 (PanSTARRS) survive perihelion?

There is a possibility that the comet C/2021 O3 (PANSTARRS) won’t survive perihelion. This conclusion is based on John Bortle's empirical relation on long-period comet survivability. Moreover, further observations revealed the comet’s faintness and slow rate of brightening. All this, plus the fact that the comet will pass very close to the Sun, may indicate that C/2021 O3 (PANSTARRS) might disintegrate.

C/2021 O3 (PANSTARRS) vs C/2021 A1 (Leonard)

Of course, when it comes to comets, we all remember Leonard — the most spectacular comet of 2021. Are there any similarities between it and C/2021 O3? Let’s quickly compare these two space objects.

C/2021 A1 (Leonard) was first detected at a distance of 5 AU at a magnitude of about 19. C/2021 O3 (PANSTARRS), in its turn, was discovered at a distance of 4.3 AU, at a magnitude of 20.

Leonard became the brightest comet of 2021. At the end of December, most stargazers were able to observe it as a borderline naked-eye object, which varied in magnitude from 3 to 6. However, the comet disintegrated during its perihelion on January 3, 2022.

It is still unclear whether C/2021 O3 (PanSTARRS) will survive its approach to the Sun. Even if it does, we won’t be able to see it without optical devices, according to forecasts.

Next comets visible from the Earth

If C/2021 O3 (PANSTARRS) disintegrates, we still have other comets to look for in the sky this spring:

  • C/2019 L3 (ATLAS) can be observed from both hemispheres in the evening. The magnitude of the comet will be around 9.
  • C/2017 K2 (PANSTARRS) gets brighter and might appear in the morning sky, breaking the magnitude 10 level in mid-April. In May, it is expected to be observable from both hemispheres at a magnitude of 8.
  • by the end of April, C/2021 E3 (ZTF) might brighten to 10.2 magnitude and become a morning object for the southern observers.
  • C/2021 F1 (Lemmon-PANSTARRS) will be too close to the Sun but might appear in the sky by mid-May for observers from the Southern Hemisphere, shining at a magnitude of 11.

Keep in mind that comets are very unpredictable, and all data (especially the magnitude forecasts) can quickly change. We’ll keep you updated!

We wish you clear skies and happy observations!