Sarbani Basu is the William K. Lanman Jr. Professor of Astronomy, Yale University.

Prof. Basu was trained in India and moved to the US after conducting post-doctoral work in Europe (UK and Denmark). In the US, she worked at the Institute for Advanced Study, Princeton, NJ, before moving to Yale as an assistant professor in 2000. She specializes in the study of the Sun and other stars using data on solar and stellar oscillations (star quakes Among her most significant early results were (1) determine the sound-speed and density profiles of the solar interior by inverting the oscillation frequencies, which in turn allowed her to show that the so-called “solar neutrino problem” was not a result of deficiencies in our solar models, we now know that this is a particle physics problem, (2) determine the amount of helium in the out layers of the Sun, the solar surface is not hot enough to allow us to determine the amount of helium through spectroscopy and yet helium plays a critical role in the evolution of a star, (3) determined the exact location of the base of the solar convection zone and show that there has to be mixing below the convection zone; extra mixing is not a standard ingredient of solar models, (4) showed that the shear layer below the solar convection zone was extremely thin, and that there is an upper limit of 0.3 Mega Gauss on the strength of the magnetic fields there, this shear layer is believed by many to be the seat of the solar dynamo that is responsible for the magnetic cycle of the Sun.

By the time Prof. Basu joined Yale, the different helioseismology projects had accumulated data for five years during the ascending phase of Solar Cycle 23, enabling her to determine the changes that take place within the Sun as the solar cycle progresses. These data have allowed her, along with her students and collaborators, to show that there are marked changes in the internal Dynamics of the Sun. The shear layer at the base of the convection zone changes too, but the changes in Cycle 23 were not the same as the changes in Cycle 24, a result we are struggling to explain. She also showed that the structure of the outer layers of stars is not spherically symmetric. While finding solar-cycle related changes in solar dynamics is relatively easy, detecting changes in solar structure has proved challenging, though in 2021 she found that structural changes are indeed detectable.

Prof. Basu has several honors to my name. She was awarded the George Ellery Hale Prize of the Solar Physics Division of the American Astronomical Society in 2018 for her work in understanding the structure and dynamics of the Sun and other stars. Earlier, in 1996, she was awarded the Vainu Bappu medal of the Astronomical Society of India for her early work on the helioseismic characterization of the interior structure of the Sun. Additionally, she was elected as a Fellow of the American Association for the Advancement of Science in 2015, and a Fellow of the American Astronomical Society in 2020 (this was the AAS’ first batch of Fellows).