JWST Spots 14 Emerging Star Clusters in NGC 628
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- JWST's NIRSpec instrument observed NGC 628 as part of the FEAST (Feedback in Emerging extrAgalactic Star clusTers) program, characterizing 14 emerging young star clusters (eYSCs) still partly embedded in their natal dust cloud.
- Helena Faustino Vieira of Stockholm University led the international team; results were published March 10 on the arXiv pre-print server.
- The observations detected helium and hydrogen recombination lines, multiple molecular hydrogen transitions, and bright 3.3 µm PAH emission tracing photodissociation regions still associated with the eYSCs.
- Measured ionizing photon fluxes suggest that stars of spectral types O8.5V–O8V dominate the emission from the eYSCs.
- The eYSCs have a median age of 3 million years, while more evolved clusters with red supergiant signatures are estimated at more than 9 million years old.
- NGC 628 (also known as Messier 74) sits roughly 30 million light years away, has a star-formation rate of 1.7 solar masses per year, and is estimated to be 10–13 billion years old.
Why it matters: Emerging young star clusters are invisible to optical surveys because they remain buried in dusty natal clouds, leaving a blind spot in our understanding of the earliest phase of star cluster evolution. JWST's infrared spectroscopy opens that previously inaccessible window, giving astronomers a concrete sample of 14 eYSCs with measured ages, stellar populations, and PDR morphology to anchor models of stellar feedback and galaxy assembly.
