SIMBAD references

Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope of four chemical peculiar stars is presented and analyzed. The peculiar Hg-Mn star α And is found not to be a photometric variable within the errors of measurement contrary to some published studies. Observations of the magnetic CP star HD 184905 were used to refine the zero epoch and the period which was found to be 1.85435 days. Our photometry and that of Morrison & Wolff are generally quite similar. We find evidence for two sub-minima within the broad minimum in both u and y. The cool magnetic CP star HR 8216 is non-variable in agreement with previous studies that suggested it was constant or a very long period variable. The CP star HR 8434 has a period of 1.43242 days and shows a generally in phase variation of u, v, b, and y. The light curves have two nearly equally maximum and a sharp minimum. The largest amplitude is for u, 0.085 mag.