Media Information and Press releases

Media Information and Press releases

Media Information and Press releases

Media Information

The willingness to share information of public interest

See Media Information

 

Press Release

Friday, May 14, 2021

Professor Khalack Studies the Evolution of Chemically Peculiar Stars


Professor Viktor Khalack


View Full-Size Image

Our understanding of the true nature and fate of our sun is based on the current knowledge of stellar evolution. That is precisely what Professor Viktor Khalack from the Department of Physics and Astronomy at the Université de Moncton keeps in mind during his research of chemically peculiar (CP) stars.

Dr. Khalack is working with an international team of astrophysicists from Canada, Germany, Chile, the United States, France, and Sweden. His research has earned him observational time with the Transiting Exoplanet Survey Satellite (TESS) space telescope, at the Canada-France-Hawaii telescope (CFHT), at the telescope Bernard Lyot (TBL), as well as at the Mont Mégantic Observatory.

Summary of Research

Modern simulations of stellar evolution can explain the diversity of observed global parameters, such as surface temperature, in different populations of stars. However, the evolution of stars with a strong magnetic field and peculiar chemical abundance observed on their surfaces are not yet fully understood.

To develop an accurate evolutionary scenario for CP stars, one must first collect data for a large sample of CP stars having differing ages and exhibiting different types of chemical peculiarity. Professor Khalack investigates signatures of atomic diffusion in CP stars through the analysis of their high-resolution spectra. He also studies photometric variability (rotational modulation and stellar pulsations) of CP stars using data provided by the TESS space mission. Atomic diffusion is a physical process whereby atoms of certain elements are pushed towards the surface by the radiation field emanating from a star, whereas other elements that absorb less radiation diffuse towards the deeper layers of the star. This phenomenon affects the abundance of elements observed on the surface of stars.

The first part of Professor Khalack’s research involves spectral observations of CP stars with the large world’s telescopes like CFHT and TBL. The high-resolution and high signal-to-noise spectra of CP stars are required to perform abundance analysis and estimate their global stellar parameters. Dr. Khalack has created a semi-automatic software that can provide detailed information on the stratification of elements’ abundance with depth in the outer layers of stars (which are usually called a stellar atmosphere).

The second part of his research involves analysis of photometric data provided by the TESS space telescope with aimto select and study a sample of magnetic CP (mCP) stars. Professor Khalack has created a stand-alone software (TESS-AP) that automatically analyzes data of 200,000 stars observed by TESS and performs their characterization. Using the obtained results one can select a sample of stars with the required photometric variability and global stellar parameters. This approach allows Professor Khalack to identify mCP stars and study their variability including stellar pulsations. Analysis of stellar pulsations (or asteroseismology) helps to estimate the global stellar parameters and age of the studied CP stars.

Professor Khalack’s research is funded by the Natural Sciences and Engineering Research Council of Canada, the Mitacs Globalink program, and the Faculty of Graduate Studies and Research and the Faculty of Science at the Université de Moncton.




Return to Press release