Preparing for Comet C/2024 S1 (ATLAS)

Fri, 10/25/2024 - 10:13 — Elke D'Huys

Just like everywhere else in the world, the halls of the P2SC have been buzzing with conversations on the comet named C/2023 A3 (Tsuchinshan-ATLAS) and whether or not we could observe it from our backyards.

However, another comet was discovered quite recently by Hawaii's Asteroid Terrestrial-impact Last Alert System (ATLAS) project and named C/2024 S1. This one is of much more interest to the PROBA2 team as it is a sungrazer. Those comets travel very close to the Sun, where they light up and often break into smaller pieces.

We have observed on of these comets before: in 2011 SWAP caught comet Lovejoy on camera. SWAP showed the comet as a bright streak in the solar corona, with interactions between the comet tail causing brief coronal brightening and wiggles in the comet’s tale. This was only the second time ever that a comet has been observed through an extreme-ultraviolet (EUV) solar telescope. To our surprise it even survived its passage through the hot solar corona.

Click on the image to see the SWAP observations of Lovejoy.

On October 28, C/2024 S1 will reach its closest point to the Sun. Many solar observatories around the world are preparing special observation campaigns to try and catch this comet as it speeds by. There are many unknowns about the composition and brightness of this object, making the planning of the observations quite challenging. Nevertheless, our SWAP telescope will be watching closely to see whether the comet survives its close encounter with our hot star. If SWAP is able to see the comet, the observations could yield important information both about comets, the solar corona, and the sun's complex magnetic field.

The image below shows the trajectory in the PROBA2/SWAP field-of-view. PROBA2 will conduct two off-point maneuvers as the comet passes the Sun Thursday evening, making use if its large field-of-view and flexible pointing capabilities to capture some hopefully unique images of this comet.