The observable properties in a star are governed by the physical structure of the stellar
atmosphere. Stars exhibit a progressive decrease in intensity from the centre to the edge of
the disc, a phenomenon known as limb darkening (LD). This arises due to the temperature
gradient and opacity structure within the stellar atmosphere. If not properly accounted for,
it can introduce errors of up to 3% in the estimated stellar radius, which then propagate into
other derived fundamental parameters. Although there have been many attempts to study
LD over time, most studies have focused on only a small number of stars, and there is still
no homogeneous analysis across a large and diverse sample of stellar spectral types.
Modern stellar interferometers can resolve a significant number of stars and attain the
second lobe of visibility. This provides an excellent opportunity to study LD, which can be
accurately determined by observations performed beyond the first visibility minimum. The
Interferometric Survey of Stellar Parameters (ISSP) is designed to take advantage of SPICA
at CHARA, alongside MIRCX (H band) and MYSTIC (K band), to conduct multiwavelength
observations of hundreds of stars. One of the primary objectives of the programme is to
estimate LD angular diameters with uncertainties less than 1% and to create a
homogeneous catalogue. The parameters measured or derived from this survey are
also invaluable for upcoming large-scale space missions such as PLATO.
Interferometric observations alone are not enough to obtain an accurate estimation of the
effective temperature and the surface gravity of the star. To address this, I have designed the
Pipeline for Interferometric Measurements of Stars (PIMS) using a novel method combining
interferometry with spectroscopic and photometric observations. Exploiting the PIMS, I fitted
45 stars from the ISSP programme, including 28 giants, 6 subgiants and 11 dwarfs. From
these observations, the angular diameter was estimated with an average accuracy of 0.78%.
The achieved accuracies for effective temperature, radius, and surface gravity are
approximately 2.2%, 3.2%, and 13%, respectively. The resulting parameters were compiled
and analysed in detail. In addition, I investigated the LD behaviour of 14 large stars in the
sample by comparing limb-darkening coefficients derived from interferometric observations
with those obtained from fitted models.
