High Precision Infra-Red Stellar Interferometry
by Benjamin F. Lane
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(free download) Synopsis
This dissertation describes work performed at the Palomar Testbed Interferometer
(PTI) during 1998-2002. Using PTI, we developed a method to measure stellar
angular diameters in the 1-3 milli-arcsecond range with a precision of better
than 5%. Such diameter measurements were used to measure the mass-radius relations
of several lower main sequence stars and hence verify model predictions for
these stars. In addition, by measuring the changes in Cepheid angular diameters
during the pulsational cycle and applying a Baade-Wesselink analysis we are
able to derive the distances to two galactic Cepheids (h Aql & z Gem) with
a precision of ~10%; such distance determinations provide an independent calibration
of the Cepheid period-luminosity relations that underpin current estimates
of cosmic distance scales.
Second, we used PTI and the adaptive optics facility at the Keck Telescope
on Mauna Kea to resolve the low mass binary systems BY Dra and GJ 569B, resulting
in dynamical mass determinations for these systems. GJ 569B most likely contains
at least one sub-stellar component, and as such represents the first dynamical
mass determination of a brown dwarf.
Finally, a new observing technique, dual star phase referencing, was developed
and demonstrated at PTI. Phase referencing allows interferometric observations
of stars previously too faint to observe, and is a prerequisite for large-scale
interferometric astrometry programs such as the one planned for the Keck Interferometer;
interferometric astrometry is a promising technique for the study of extra-solar
planetary systems, particularly ones with long-period planets.