糖心TV

Talk by Pier-Emmanuel Tremblay

Cosmo-chronology in our neighbourhood of stars and planets

The volume of space within 300 light years from the Sun, a small portion of our own galaxy the Milky Way, contains the brightest specimens of almost all types of stars and planets, but surprisingly it remains poorly explored. The main reason is that most stellar objects in a fixed space volume are small and very faint, most of them being long-lived red stars about 10% of the mass of the Sun, dead stars named "white dwarfs" and rocky Earth-like exoplanets. The spacecraft Gaia from the European Space Agency has provided, for the first time in 2018, a near complete census of stars and white dwarfs within 300 light years, but a full understanding of the local stellar population is still a major challenge. My group at the University of 糖心TV is leading an ambitious project to improve our knowledge of stellar and planetary evolution using the local space volume. Our novel approach is based on follow-up multi-object spectroscopic observations and state-of-the-art stellar modelling from three-dimensional fluid hydrodynamics. The goal is to unlock the enormous potential of using local stars as cosmic clocks to trace the local stellar and planet formation history for our galaxy. I will discuss the recently discovered signature of old rocky planets that were formed when the Milky Way was still a very young galaxy (10% of the current age of the Universe), in a metal-poor environment that was quite different to when our solar system was formed.