Shaking stars to get to their cores

Benard Nsamba receives prestigious fellowship to study stars and inspire Ugandan students

On 23 August 2021, the 'Branco Weiss Fellowship – Society in Science’ announced that Dr. Benard Nsamba of the Max-Planck Institute for Astrophysics (MPA) in Garching, Germany, was selected as one of eight new fellows after an extended global recruitment campaign. The fellowship is giving Benard Nsamba up to five years of complete academic freedom to do interdisciplinary research at any institution in the world. As a Branco Weiss Fellow, Benard Nsamba will combine stellar observables such as seismic data from space missions with stellar luminosities and spectroscopic data to tightly constrain stellar models. This technique offers a path towards a robust exploration of stellar interior structure.

Asteroseismology, i.e. the study of stellar oscillations, has emerged as a very promising avenue to gain detailed information on the structure and physics of stellar interiors. Due to the advances in exoplanet research, high-quality photometric data has become available also on their host stars from space missions such as the French-led CoRoT satellite, NASA’s Kepler space telescope, and more recently, NASA’s TESS. This seismic information can be combined with ‘classical’ data to constrain stellar models and explore the impact of stellar interior physics.

One particular research focus for Benard Nsamba is the nature and size of stellar cores and how these are affected by convective core overshoot, rotation, metallicity mixtures, and atomic diffusion. Matching stellar observables to stellar evolution models will require skills in photometry/asteroseismic data analysis, spectroscopic analysis, as well as stellar modelling. In addition to contributing to theories of stellar structure, stellar dynamics and evolution, Benard Nsamba’s project will also play a significant role in the ongoing preparation activities concerning the precision and accuracy of exoplanet-host star characterisation for ESA’s PLATO (PLAnetary Transits and Oscillations of stars) mission.

In addition to his scientific research into the heart of stars, Benard Nsamba will use astronomy as a tool to stimulate the interest of high school students in STEM (science, technology, engineering, and mathematics) subjects, and encourage and motivate them to consider science related careers. Astronomy is considered to be a stimulating, appealing subject, and an excellent tool for conveying scientific knowledge to young students also in Africa – Benard Nsamba got interested in astronomy in general and stars in particular early on in his studies, with his undergraduate project focussing on designs of refracting telescopes and his master thesis on mass-loss in red giant stars. After studying physics at the Mbarara University of Science and Technology (MUST) in Uganda, Benard Nsamba obtained his PhD at the Institute of Astrophysics and Space Sciences (IA), University of Porto in Portugal in 2019 working on astroseismology of Sun-like stars. Since 2020, he is working in the Stellar Evolution Group at the MPA as an Alexander von Humboldt Fellow.

“Astroseismology, or star-quakes, is a very exciting avenue to obtain information from deep inside stars much like our Sun,” points out Selma de Mink, the stellar astrophysics director at MPA. “It is a great honour to host Benard Nsamba and support him not only in his scientific endeavours but also in using science to reach out to young people in Uganda. We hope that his example will inspire many future scientist all over the world!”

More information

The Branco Weiss Fellowship – Society in Science was founded in 2002 to provide a platform for researchers in the natural sciences and engineering who are aiming to extend their scientific work to cover specific social and cultural questions and perspectives. The fellowship is now managed by the ETH Zurich (Swiss Federal Institute of Technology Zurich). It was initiated and financed by the Swiss entrepreneur Dr. Branco Weiss, who passed away 2010, to support scientists after their PhD and before their first faculty appointment who have conceived an original and independent research idea that falls outside the scope of large-scale research projects. To qualify for the prestigious grant, candidates must provide evidence of outstanding scientific achievement, but also demonstrate social commitment and communication skills. This year, there were 470 applications for the Branco Weiss Fellowship, from which the eight awardees were chosen in a rigorous evaluation process.

For more information on The Branco Weiss Fellowship, please visit www.brancoweissfellowship.org