Comet C/2022 E3 (ZTF)

On January 12, 2023, comet C/2022 E3 (ZTF) reached its closest approach to the Sun, and later on February 1, its closest approach to Earth. In those days close to perihelion, comets experience the most significant changes in their structure, leaving us with a wonderful spectacle.

From the Observatorio de Aras de los Olmos we have witnessed this daily evolution live. Since the beginning of January, PixInsight Team members Vicent Peris and Alicia Lozano have been photographing the comet to show us its behavior in the form of a timelapse. You can watch the video on the official PixInsight YouTube channel:

Links to the Images and Related Material

ZTF Comet Chronicle

In the first images of the video you can see the antitail of the comet, an optical illusion that we perceive from our perspective due to the crossing of our planet by the orbital plane of the comet. However, during the first half of January, the comet still had a more traditional appearance with its dust and ionic tails:

Comets generate a temporary atmosphere due to the solid particles of dust that break off from their nucleus. This material, swept by the solar wind, gives rise to the formation of the characteristic dust tail as it approaches the Sun. Often, the formation of an ionic tail also occurs due to the ionization of the particles by the solar wind. These particles, being electrically charged, remain aligned with the Sun's magnetic field, forming a straight line. The most interesting thing to highlight in these images is the smooth fluctuation of that ionic tail and the details that can be observed in it.

On the night of January 18-19, we caught a disconnection of material from the ion tail. In the following mosaic we show the evolution of this event:

We believed that this event would decrease the strength of the ionic tail, but at dawn on the 23rd, we were able to capture the exit of a jet that led to the reactivation of this tail, as shown in the two images below, separated by an hour and a half.

We could observe the antitail better these nights since its maximum visibility had been predicted for January 22. On the other hand, the reactivation of the ionic tail became evident the next day, being noticeably longer and brighter:

On the weekend of January 28-29, we had the comet in an unusual circumpolar position, about 13 degrees from Polaris, giving us the unique opportunity to observe the comet throughout the night. The following photograph shows the comet next to the North celestial pole over one of the domes of the Observatorio de Aras de los Olmos.

In the time-lapse shown in the video, we can see the comet's path during the night of January 28 to 29. After the Moon sets, we see a strong airglow in the sky. This airglow is produced by light emission due to the restructuring of the particles of the atmosphere that have been ionized during the day by sunlight. The visibility of this phenomenon is a good indicator of the quality of the sky that we can enjoy in Aras de los Olmos. In the following crop, the light from all the photographs has been added to show the movement of the stars in the sky. If we look closely, one of these arcs does not follow the same trajectory and is also green: it is the arc of the comet flying among the stars.

In the following image, acquired on January 29, we were lucky enough to capture a faint orange tail. This is a rare event in comets, and it must have lasted only a few hours. The tail, of a well-differentiated color to the typical bluish one, is due to the presence of sodium.

The last nights of observation also offered us an unusual spectacle. Due to a change in perspective, the ion tail underwent a 120-degree turn in just five days. You can watch it at the end of the video. Below we show a mosaic with several of the images from these nights:

Finally, after this turn, the ionic tail began to decrease in activity until it almost disappeared in the images of February 2. Right now, the comet is moving away from Earth, and most likely it will be expelled from the solar system, so it will be impossible for it to revisit us.