Science Café, Thursday June 4, 7:30p
Daily
Planet Auditorium
Speaker: Anna Frebel
Searching for the oldest stars
Take a walk on a moonless night. Watch the Milky Way above, made from a myriad of stars. Did you know that some of them have been shining for more than 13 billion years? These are the oldest, still surviving, objects in our 13.8 billion years old universe. "Stellar archeology" identifies these extremely rare relics. Analysis of their chemical composition shows that they contain only trace amounts of heavy elements (e.g. calcium, iron) because these stars formed at a time when little of these elements existed. This offers the extraordinary opportunity to use local Milky Way stars for exploring the earliest times in the universe. This work has revealed tantalizing details about the shortlived very first stars which cannot be studied otherwise. When they exploded as supernovae they left behind individual element signatures in the surrounding gas clouds. These "chemical fingerprints" were incorporated into the next generation longlived stars that we still observe today. Having access to these fingerprints also provides exclusive information about element nucleosynthesis, chemical evolution, early star and galaxy formation processes, and even the formation of the Milky Way. Being at the forefront of this field, the author offers an intriguing account of the latest research results paired with a unique insight look into the life as an astronomer. Having discovered several of the oldest and most primitive stars using the world's largest telescopes she tells fascinating discovery stories that allow the audience to witness what it means to be a scientist in this day and age. Spectacular video clips about observing with the 6.5m optical Magellan telescopes in the Atacama desert in Chile will be shown.