Did JWST Find an Exomoon or a Starspot?

Searching for exomoons – moons the orbit around another planet – was one of the most exciting capabilities expected of the James Webb Space Telescope (JWST) when it launched in late 2021. So, after four years of operation, why hasn’t it found one yet? Turns out it’s really, really hard to find a moon around a planet light-years away. A new paper available in pre-print on arXiv from David Kipping of Columbia University (and Cool Worlds YouTube Channel fame) shows why. They used 60 hours of time on JWST’s NIRSpec instrument and weren’t able to definitively confirm the existence of a possible exomoon.