EPFL researchers conduct high-precision Cepheid measurements

20 June 2024 09:04

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Lausanne - Researchers at the Swiss Federal Institute of Technology Lausanne (EPFL) are playing a leading role in the high-precision measurement of Cepheid star velocities. Astronomers hope to use the results to draw conclusions about the size of the universe.

Researchers at the Institute of Physics of the Swiss Federal Institute of Technology Lausanne (EPFL) are involved in measuring the speed of Cepheids within the context of the international VELOCE program. According to a press release, the team led by Richard I. Anderson was able to conduct precise measurements of radial velocities using sophisticated spectrographs. Cepheids are stars that change in brightness over a cycle of days to weeks. Measurements of these pulsations can be used to draw conclusions about the size and scale of the universe. The international project VELOcities of CEpheides (VELOCE; Italian for rapid) was started to enable more accurate velocity measurements. Under the leadership of Anderson, researchers at EPFL, the University of Geneva, and Belgium’s KU Leuven are involved in this project. The measurements have been made by the Swiss Leonhard Euler Telescope in Chile and Belgium’s Mercator telescope on the island of La Palma over a period of twelve years. The research results now being presented represent the analyses of 18,000 high-precision measurements of 258 Cepheid radial velocities.

Richard I. Anderson, an astrophysicist and research leader at EPFL, commented in the press release: “Tracing Cepheid pulsations with high-definition velocimetry gives us insights into the structure of these stars and how they evolve.” He went on to add: “In particular, measurements of the speed at which the stars expand and contract along the line of sight – so-called radial velocities – provide a crucial counterpart to precise brightness measurements from space.” ce/eb

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