On the possible variability of the main sequence A stars θ Virginis and 109 Virginis^*

Department of Physics, The Citadel, 171 Moultrie Street, Charleston, SC 29409, U.S.A.

Received: 17 December 1996
Accepted: 6 February 1997

Abstract

Differential Strömgren uvby photometric observations from the Four College Automated Photoelectric Telescope are used to examine the possible variability of the spectrophotometric standards θ Vir and 109 Vir. No evidence is found for variability within a season of observation. Small year to year differences are most likely due to unaccounted for extinction changes.