Professor (emeritus) Jan-Erik Solheim: "The swinging blue subdwarfs - discovery of a new class of pulsating stars"

I shall tell the story of the discovery of the new class of pulsating sdB stars. In this case theoretical predictions and observations were done at the same time and independently, about 10 years ago. The sdB stars are hot and blue and populate the Extreme Horisontal Branch. They are also considered responsible for the UV upturn in spectra of galaxies, and more than half of them seem to be in binary systems. Their pulsating periods are between 100 and 500s and only one in 10 with the predicted gravity and surface temperature pulsate. At the Nordic Optical telescope we have conducted a very successful search program, detecting more than 1/3 of the known pulsators in this family which now counts nearly 40.