Variable stars and the distance scale
We use STELLA to improve the calibration of the extra-galactic distance
scale in several ways. One way is to determine individual distances to
nearby weakly reddened Cepheids using the infra-red surface brigthness
method. Comparing the resulting luminosities for these solar metallicity
stars with metal poor Cepheids from the Small and Large Magellanic Cloud
we can constrain the effect of metallicity on these luminosities.
Another way is to study nearby weakly reddened eclipsing binaries with
accurate Hipparcos, and soon GAIA, parallaxes to calibrate the near
infrared surface brightness relation. This will bring down the already
small uncertainty on the eclipsing binary distance to the LMC and
provide an important consistency check on the GAIA Cepheid distance
scale.