During its recent passage near Earth, comet 12P/Pons-Brooks appeared to develop an unusual second tail, creating a rare optical illusion known as an anti-tail. This green and explosive comet provided a fascinating spectacle, photographed by astrophotographers in Namibia.
Comet 12P/Pons-Brooks with an anti-tail (on the right) photographed on June 3.
Credit: Michael Jäger, Gerald Rhemann, and Lukas Demetz
The 17-kilometer (10.6 miles) diameter comet 12P gets its green hue from diatomic carbon present in its tail and coma. Being of a cryovolcanic nature, it periodically ejects jets of gas and ice when solar radiation heats its icy core. These eruptions create a brighter coma, increasing the comet's luminosity.
In an elliptical orbit around the Sun, 12P spends most of its time in the Oort Cloud. However, over the past year, it has traversed the inner Solar System, triggering multiple eruptions that earned it the nickname "Devil's Comet" due to its apparent "horns."
After its closest approach to the Sun on April 21, 12P came closest to Earth on June 2 at a distance of 1.5 astronomical units (about 140 million miles). The next day, astrophotographers captured a striking image showing the comet's anti-tail, an unusual optical structure that seems to defy the laws of physics.
Unlike a normal comet tail formed by solar winds, the anti-tail appears to point towards the Sun. This illusion is created when Earth passes through the comet's orbital plane, illuminating the debris left in its wake.
12P with "horns" during its initial eruptions.
Credit: Comet Chasers/Richard Miles
Anti-tails of comets are relatively rare, the last one being observed on comet C/2022 E3 (ZTF) in February 2023. Before that, anti-tails were seen on comets Kohoutek in 1973, Hale-Bopp in 1997, and PanSTARRS in 2013.
This is not the first time 12P has captured attention. In April, its main tail was temporarily stripped away by a solar storm. Currently on its way back to the outer Solar System, 12P will not return to our skies until 2095.