Quick blurb in Astronomers’ Telegram:
www.astronomerstelegram.org/?read=17538
Jehin, E. Hmiddouch, S. Aravind, K. et al. TRAPPIST bright comets production rates: 3I/ATLAS, 24P/Schaumasse, C/2025 T1 (ATLAS), C/2025 K1 (ATLAS) and C/2025 R2 (SWAN)
on 10 Dec 2025: 22:50 UT
Besides covering multiple comets, coverage of interstellar object 3I/ATLAS continues from multiple, corroborating orgs. Here, the TRAPPIST system (TRAnsiting Planets and PlanetesImals Small Telescope) chimes in. TRAPPIST is, officially, an exoplanet search system, using telescopes with staring coverage and high-precision pixels to monitor stars for occultations. If an exoplanet crosses in front of its host star, that star dips in brightness. Since just a few percent of planetary systems align with Earth, and then cross their stars, it takes a large dataset of stars to detect those precious few. These exoplanet programs, then, use wide-field telescopes to cover thousands of potential planet hosts. In turn, their wide fields mean a good chance of catching other targets.
Targets like… ATLAS, and other comets. By chance, the TRAPPIST array catches such moving, variable bodies. Parsing TRAPPIST’s dataset then delivers this bonus science. As comets approach towards, then recede from the Sun, they warm and cool, and activate/deactivate. Tracking this activity (their “light curve”) in turn implies their volatile composition.