  In order to understand the exoplanet, you need to understand its parent star.
Astrophysical parameters of extrasolar planets are directly and indirectly
dependent on the properties of their respective host stars. These host stars
are very frequently the only visible component in the systems. This book
describes our work in the field of characterization of exoplanet host stars
using interferometry to determine angular diameters, trigonometric parallax to
determine physical radii, and SED fitting to determine effective temperatures
and luminosities. The interferometry data are based on our decade-long survey
using the CHARA Array. We describe our methods and give an update on the status
of the field, including a table with the astrophysical properties of all stars
with high-precision interferometric diameters out to 150 pc (status Nov 2016).
In addition, we elaborate in more detail on a number of particularly
significant or important exoplanet systems, particularly with respect to (1)
insights gained from transiting exoplanets, (2) the determination of system
habitable zones, and (3) the discrepancy between directly determined and
model-based stellar radii. Finally, we discuss current and future work
including the calibration of semi-empirical methods based on interferometric
data.
