Department of Astronomy & Physics
Congratulations to Dr. Dan Majaess who successfully defended his Ph.D. thesis, "Constraining the Impact of Metallicity on Cepheid Distances via a Refined Galactic Calibration." Supervisor Professor David Turner. Committee: Professors Phil Bennet, Ian Short, and Tom Barnes (University of Texas).
To paraphrase the abstract from Dan's thesis, Dan presented evidence implying that the classical Cepheid VIc period-Wesenheit function is relatively insensitive to metallicity. His results indicate that variations in chemical composition among Cepheids are a comparatively negligible source of uncertainty for VIc Wesenheit-based period-luminosity (PL) relations and extragalactic distances, for determinations of Ho, and for the selection of a cosmological model. His conclusions rest in part on a Galactic classical Cepheid PL calibration that was revised using near-infrared JHKs photometry for new and existing clusters containing Cepheid variables.