Comet Nishimura’s tail ripped off by a CME

On September 2, 2023, a coronal mass ejection (CME) launched by our sun hit Comet Nishimura (C/2023 P1), causing a disconnection event and stripping its tail. This encounter occurred while the comet was located about halfway between the orbits of Mercury and Venus.

Comet Nishimura (C/2023 P1) is currently on a journey towards the sun, with its close encounter anticipated on September 17, 2023, at a distance of 0.22 AU. During its transit, the comet experienced a significant phenomenon known as a “disconnection event” on September 2, 2023. This event, caused by a CME, resulted in the detachment of its tail. Such events aren’t entirely novel; in April 2007, Comet Encke experienced a similar fate when its tail was completely torn off by a CME, as witnessed by NASA’s STEREO-A spacecraft.

Now positioned at 0.48 AU, approximately halfway between Mercury and Venus, Comet Nishimura is more susceptible to the impacts of CMEs. These solar events are denser and more potent in these proximities compared to when they approach Earth at 1.0 AU.

Dr. Tony Phillips from SpaceWeather.com said that the CME responsible for the recent disconnection event most likely originated from active sunspot AR3413. The trajectory and timing of this CME were optimal for the observed disconnection event on the comet.

Post the disconnection event, Comet Nishimura’s tail has regenerated. However, it remains vulnerable to future solar activities. Observations from SOHO on September 5, 2023, indicated at least two CMEs moving in a direction that might intersect with the comet’s path. If these CMEs strike, the reformed tail might be at risk again.

References:

¹ The sun just ripped off a comet’s tail – Space Weather – September 5, 2023

Featured image credit: Michael Jäger @Komet123Jager (stillshot)