Kepler and TESS were built to find planets, by catching the small dip in a star's brightness when a planet passes in front of it. To do that they measure the brightness of very many stars almost without interruption for weeks or years. The same measurements show the tiny brightness changes caused by stellar oscillations, which is why asteroseismologists use them for more than a hundred thousand stars.
NASA launched Kepler on 6 March 2009. It watched about 150,000 stars in one patch of sky in Cygnus, then, as the K2 mission, observed fields along the ecliptic in 19 campaigns of about three months, until it ran out of fuel and was retired on 30 October 2018. Its data gave oscillation measurements for 16,094 red giants (Yu et al. 2018). TESS, launched on 18 April 2018, observes the sky in strips of 24 by 96 degrees for about 27 days each, and its first two years yielded 158,505 oscillating red giants (Hon et al. 2021).
Where I come in
Since 2022 I have been a member of the Kepler Asteroseismic Science Consortium, in its red-giant oscillations working group, and an affiliate of the TESS Asteroseismic Science Operations Centre. For my PhD I built a pipeline that combines TESS, Kepler/K2, Gaia DR3 and 2MASS data with PARAM to estimate stellar ages. In July 2024 I was on the local organising committee of the TASC8/KASC15 workshop in Porto, and at TASC10/KASC17 in Aarhus in July 2026 I gave a talk on JANUS, which learns the chemistry of TESS asteroseismic red giants from Gaia spectra.