A tale of two stars: analysis of light variations in candidate Slowly Pulsating B and Gamma Doradus variables.

Both HD199122 and HD213617 are found to be periodic with frequencies within the characteristic range of g-mode pulsation for either the Slowly Pulsating B Stars (SPBs) or the Gamma Doradus stars. We originally began observing HD199122 as a SPB based on its appearance in the list of such stars found through Hipparcos data examination by Koen (MNRAS, 321, 44, 2001). However, as noted by Koen, its reported spectral type A2 is late for a SPB. Based on published photometric indices, he suggests that its spectral type is closer to B7, and thus, it is likely to be a SPB. Using Stromgren uvby photometry, we have examined over 600 differential measures of this star. We find two clear frequencies of f1 = 0.80209 c/d and f2 = 0.8244 c/d, which is within the characteristic range for g-mode pulsation of hotter main sequence stars. Our data suggests the possible presence of a third frequency, but confirmation is pending more data analysis. A preliminary analysis of Hipparcos satellite data for HD213617 proposes a frequency of 0.55672 (Handler, G., MNRAS, 309, L19-L23, 1999). However, Castellano (private communication) has found a period closer to 0.8 c/d from his analysis of the Hipparcos data. Since this star is an early F star, confirmation of this pulsational value could classify this star as a Gamma Doradus variable. We are presently obtaining observations for both subjects and will continue analysis as data arrives.

* Observations of HD213617 were begun as part of a summer project during the NASA Academy at Ames. This work has been supported by South Carolina Space Grant and NSF grant AST--0071260 to the College of Charleston.