Let’s get caught up again with arXiv preprints:
Earth and Planetary Astrophysics > arxiv.org/abs/2601.15443
Tan, H. Yan, X. Li, J-Y. Perihelion Asymmetry in the Water Production Rate of the Interstellar Object 3I/ATLAS
[Submitted on 21 Jan 2026]
arxiv.org/abs/2601.16983
Hoogendam, W. B. Jones, D. O. Yang, B. et al. Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS
[Submitted on 23 Jan 2026]
arxiv.org/abs/2601.17083
Ahuja, G. Ganesh, S. Effects of different Non-Gravitational accelerations on the trajectory of Interstellar Comet 3I/ATLAS
[Submitted on 23 Jan 2026]
The comet took a while to warm up, but it did warm up. Hey, it was in deep freeze for billions of years. After perihelion (the point closest to our Sun), ATLAS is fairly warmed and now outgassing visibly. Tan et al. detail their studies of that gas, as do Hoogendam, et al. The difference is that Tan et al. go for the time change (light curve), while Hoogendam look in detail for faint spectral features, using the big Keck telescope.
Ahuja & Ganesh take a different turn, so to speak. Given this outgassing, who’s to demand that it outgas evenly and consistently? Comet emissions are typically from weak points in the mantle, forming jets. This jetting acts like a thruster, and can actually push the comet nucleus. We call this non-gravitational acceleration. Ahuja & Ganesh are on top of this acceleration.
Standard disclaimer: these are preprints, arXiv is a preprint site. The right is reserved to be wrong- these papers have not been peer-reviewed in a rigorous manner.