With a PhD from Cambridge University, Michael Perryman’s 30-year career with the European Space Agency started with his scientific leadership of Hipparcos, 1981-1997, the pioneering satellite mission which charted the distances and motions of 100,000 stars. He was co-originator of the follow-on Gaia mission, and ESA’s project scientist from its earliest concepts in 1993 until the Critical Design Review in 2008. This juggernaut mission, still operational 10 years after launch in 2013, is in the process of creating a revolutionary celestial map of two billion stars. He was Professor of Astronomy at Leiden University, The Netherlands (1993-2009), and amongst subsequent appointments, the Bohdan Paczynski Visiting Professor at Princeton University (2013), and adjunct professor at University College Dublin (since 2013). He was the recipient of the Shaw Prize in Astronomy in 2022 for his lifetime’s contribution to space astrometry.
Gaia: Mapping our Galaxy from space
The measurement of accurate star positions, astrometry, is the oldest branch of astronomy. Today, it is again at the forefront of efforts to understand the structure of our Milky Way galaxy, and how it came into existence. In this talk I will place Gaia in a historical context, briefly explain how the measurements are made, then focus on a few of the scientific highlights so far: ranging from results on individual stars (the crystallisation of white dwarfs, the tidal tails of open clusters, the nearest black hole, hypervelocity stars, and Gaia’s first exoplanets) to results on our Galaxy’s largest scales, including the distance to the Galactic centre, the discovery of halo streams (relics of the tidal accretion history of the Milky Way), measurement of our Sun’s motion around the Galaxy, and the slowing down of the `bar’ at the centre of the Milky Way due dragging by our dark matter halo.