About Jean Turner
Department chair Jean Turner is an extragalactic astrophysicist, specializing in the study of star formation in local galaxies. She received her A.B. and Ph.D. degrees at Harvard University and UC Berkeley. Before joining UCLA as professor she worked at the Harvard-Smithsonian Center for Astrophysics, and has been a Visiting Scientist at Caltech, Space Telescope, and the Joint ALMA Observatory. She has contributed to the development and commissioning of two millimeter and submillimeter telescopes. She is a fellow of the American Association for the Advancement of Science.
Research targets include the youngest regions of massive star formation. How a million stars form simultaneously in a single cluster is one of the mysteries of astronomy. There are no such young massive clusters in the Milky way, but there are in local galaxies such as the dwarf galaxy, NGC 5253. The youngest clusters are typically still "embedded" in their natal dusty gas clouds.
While this allows us to study their pristine natal environments, before the stars have had a chance to disperse the gas, it also means that they are hidden from optical view. To see them, one observes at infrared and millimeter wavelengths, where the clusters can be indirectly seen through the hot gaseous nebulae excited by the young stars. The nearby molecular clouds from which they formed can be detected in millimeter and submillimeter-wave emission from lines of molecules such as carbon monoxide (CO).
A key parameter is star formation efficiency, or how much of the natal gas cloud ends up as stars. To form a massive, long-lived cluster requires efficiencies of close to 50%; close to half of the gas cloud must become stars. Current star-forming regions in the Milky Way have efficiencies of 1-15%. Yet the Milky Way has a system of ancient globular clusters that formed 10 billion years ago, suggesting that star formation then was very different from what it is now.
Studying examples of young massive clusters forming in other galaxies can reveal how and why star formation was so different in the early Milky Way.