JWST is providing an unprecedented direct glimpse of the first galaxies in formation. This promises the opportunity to seek answers to longstanding questions in astrophysics, from the details of reionization to early metal enrichment and black hole growth. However, our answers to these questions are inextricably tied-up with questions about the earliest massive star populations. In this talk, I will describe how uniting JWST observations with detailed studies in the local Universe can provide a path towards addressing this impasse; and at the same time revolutionize our understanding of the enigmatic first few generations of massive stars. I will highlight several programs that seek to address key uncertainties in our understanding of young stellar populations at near-primordial metallicities, and how these uncertainties reflect directly on our interpretation of puzzling results at high-redshift. I will also discuss the impact of upcoming and next-generation facilities like the UVEX, the ELTs, and HWO, and the crucial roles they will play in unraveling the nature of the earliest massive stars.

Speaker: Peter Senchyna (Carnegie Science)

The 2025 Fall Colloquium talks are held on Wednesdays at 3:00 PM. This colloquium is hosted by STScI and will be held as an in-person and virtual event.

You may join in person at STScI’s John N. Bahcall Auditorium or virtually on the STScI Research YouTube channel.

Please direct questions or comments to contact above. The 2025 Fall Colloquium Committee members are: Nimisha Kumari (STScI), Elena Manjavacas (STScI), Jack Neustadt (JHU), Kevin Schlaufman (JHU), Adam Smercina (STScI), Ethan Vishniac (JHU).