NEAR-INFRARED LIGHT VARIATIONS OF CP STARS - THE SISRCREU STARS

Twelve magnetic Chemically Peculiar (CP2) stars of the SiSrCrEu subgro up mostly brighter than the 7.5 visual magnitude have been investigate d in the infrared at 1.25, 1.6 and 2.2 mu. The stars HD 74521, HD 9004 4, HD 119419, HD 125630, and HD 187473 are clearly variable in the nea r infrared with the same period as the visible light, spectrum, and ma gnetic field variations. The stars HD 10783, HD 12447, HD 116458, HD 1 47010, HD 166469, HD 170397, and HD 223640 do show a smaller amount of variability, although with quite large a dispersion of the data. A re markable result of the present investigation is that, at least for the stars for which contemporaneous observations are available, the obser ved infrared variations appear to be in phase with the variations in t he long wavelength part of the visible. This may be an indication that the mechanism of the infrared variations should be the same as for th e visible.