TESS Spotted 3I/ATLAS Two Months Before It Was Discovered

Above is a Hubble image of 3I/ATLAS captured in late July. Credit: NASA/ESA

One of the advantages of having so many telescopes watching large parts of the sky is that, if astronomers find something interesting, there are probably images of it from before it was officially discovered sitting in the data archives of other satellites that no one thought to look at. That has certainly been the case for our newest interstellar visitor, 3I/ATLAS, which, though discovered in early July, had been visible on other telescopes as early as May.

We previously reported on Vera Rubin’s detection of 3I/ATLAS well before it was officially found, and now a new paper has found the interstellar object in TESS’s data going back to early May—and it looks like it may have been “active” around that time. The study is published on the arXiv preprint server.

The Transiting Exoplanet Survey Satellite (TESS) isn’t designed to find interstellar visitors, or anything faint for that matter. As its name implies, it is designed to look at stars (which are bright) and watch exoplanets traverse in front of them, watching the host star’s light curve dip as they do.

(Source: phys.org)