The Red Clump is an overdensity in luminosity on the HR diagram, caused by certain Core-Helium Burning stars with similar core masses, a product of their evolutionary physics. We identify the exact luminosity of the Red Clump using asteroseismology, and then separately using Gaia data, to see how our assumptions about one method lead to us drawing different inferences in the other.
We find that changing asteroseismic temperature scale and/or corrections to scaling relations change the position of the Red Clump significantly, and that the corresponding parallax zero-point offset required to find that same Red Clump luminosity similarly varies significantly. It should be noted that if we assume asteroseismology to be absolute, we do not recover a parallax zero-point offset that agrees with similar work done by Zinn et al. 2018.
Clearly, there is still much to be done!