Overview/Scientific Rationale

This 5th edition of the meeting is organized in Marrakesh, Morocco , from 25 to 30 November 2024 . Previous editions took place in Visegrad, Hungary in 2015, Niepolomice, Poland in 2017, Cloudcroft, USA in 2019, and La Palma, Spain in 2022.

Cepheids and RR Lyrae stars have played a historic role in the development of astronomy in a general sense. At the beginning of the 20th century, the famous period-luminosity relation played a fundamental role in the discovery of galaxies and the expansion of the universe. The study of the properties of Cepheids and RR Lyrae stars, which is highly interesting, allows us to understand the evolutionary structure of these classes of variable stars. On the other hand, it contributes significantly to the theory of stellar evolution.

Satellite surveys like CoRoT, Kepler, TESS, and large-scale photometric campaigns such as OGLE and MACHO have generated a considerable amount of data that requires international collaboration from various perspectives. This presents an opportunity for astronomers to develop digital solutions for data acquisition and processing.

The development of astronomy in Africa has become an increasingly valuable asset for the field. Indeed, astronomy in Africa has seen significant growth due to the development of sophisticated instruments on telescopes of various sizes. The African Astronomical Society (AFAS) was established to provide a framework for research development and to support researchers in their missions. The small instruments that equip observatories recently established in Africa, particularly in Morocco at the Oukaimeden Observatory, can be highly effective in the study of RR Lyrae stars, as well as targets that require extended observation periods. Such observatories are crucial for collecting the extensive data required for such studies. The Blazhko effect and the cyclical variations in photometry continuously challenge our understanding of the atmospheric dynamics of variable stars. This phenomenon, observed in the RR Lyrae class of variable stars, requires extended periods of photometric and spectroscopic observation to hope one day to detect its origin and understand the mechanisms that take place in the cores of these stars, and consequently, to interpret it correctly.

During this meeting, we aim to focus on the development of astronomy in Africa, allowing researchers from the continent to share their expertise and experiences gained in the study of RR Lyrae and Cepheid variable stars. The gathering of theorists and experimenters will enable them to present their recent work, fostering cooperation and positioning Africa in this research field.

In addition, during this meeting from 18 to 22 November 2024, we will organize the 8th Oukaimeden Internatinal school of Astrophysics (OISA 2024) around stellar physics theme for the benefit of 30 internation al students. African students could be sponsored by the African Astronomical Society (AFAS).

MEETTING TOPICS

– Space photometry of classical pulsators
– Classical pulsators in large scale photometric surveys
– Spectroscopy and interferometry of classical pulsators
– Nonradial modes in Cepheid’s and RR Lyrae stars
– The Blazhko effect
– Classical pulsators in binary systems
– Period-Luminosity-Color relation
– RR Lyrae stars and Cepheids in stellar systems
– Classical pulsators in the era of Gaia
– Pulsations and evolution
– Numerical modeling
– Theory and pulsation models
– Future instrumentation, projects, data analysis techniques