These massive stars could explain Webb’s strangest galaxies

Astronomers are finding that the first generations of galaxies do not always behave the way existing models predict. One possible reason is that their most massive stars may have evolved very differently from massive stars in the modern Milky Way.

A new survey led by the University of Utah is using the Hubble Space Telescope to investigate those differences. The project, known as the Treasury of Extremely Metal-Poor O Stars (TEMPOS), relies on ultraviolet (UV) measurements from Hubble's Cosmic Origins Spectrograph (COS) to examine massive stars in nearby galaxies that resemble the environments found in the early universe.

The unusually large TEMPOS dataset could allow researchers to improve models of massive stars and better understand how these powerful objects influenced young galaxies. That work is becoming increasingly important as the James Webb Space Telescope, which launched in 2021, continues to uncover unexpectedly complex galaxies from the universe's early history.