Let’s keep up with our interstellar visitor, via a faster channel (arXiv.org):
Earth and Planetary Astrophysics > arxiv.org/abs/2601.22034
Belyakov, M. Wong, I. Bolin, B. T. et al. The Volatile Inventory of 3I/ATLAS as seen with JWST/MIRI [Submitted on 29 Jan 2026]
arxiv.org/abs/2601.21569
Hui, M-T. Jewitt, D. Mutchler, M. J. et al. Nucleus and Postperihelion Activity of Interstellar Object 3I/ATLAS Observed by Hubble Space Telescope
[Submitted on 29 Jan 2026]
Bringing out the big guns, clearly. The benefit of using Hubble is that, without the blurring and shimmering of Earth’s atmosphere, we can actually get use out of 2.4 meters of aperture. (In Earth’s atmosphere, a twelve inch telescope is barely being used to its full potential, and at times six inches is already affected.) And what does that 2.4 meters get us? Instead of a nucleus that’s been blurred out by its own coma (to say nothing of the atmosphere), we can separate the solid body, the gaseous environs, and the history of that gas (at least, for limited Hubble tracking).
Now, take all the advantages of Hubble, then add the ability to view in (nontrivial) infrared wavelengths. Many gases have spectral lines in the infrared and ultraviolet, while few are seen in the visible range of most telescopes. The James Webb telescope, then, can pick out not just the presence of water, CO2, CH4, etc. but also any heterogeneities (such as jetting) in those emissions. Between these two, plus lesser telescopes for good measure (literally), we’re pinning down the composition and behavior of this visitor. ATLAS looks, broadly, like a Solar System comet, but with slight differences.
Standard disclaimer: arXiv.org is for quick distribution of drafts, not necessarily high reliability on that data. Hubble has been orbiting for decades now, but JW has little direct precedent. So the authors reserve the right to be wrong. Papers on arXiv can (and have) been redrafted and re-submitted.