Our Universe consists of hundreds of billions of galaxies, and for nearby galaxies, distances are mainly measured by classical Cepheids and RR Lyrae (RR Lyr) stars. RR Lyr stars are pulsating variable ...
Ancient stars, of a type known as RR Lyrae, have been discovered in the centre of the Milky Way for the first time, using ESO’s infrared VISTA telescope. RR Lyrae stars typically reside in ancient ...