PHOTOMETRY AND LINE-PROFILE VARIATIONS OF THE PECULIAR VARIABLE GAMMA-DORADUS

Gamma Doradus is an early F dwarf with a circumstellar dust shell. It is variable in light with two nearly equal periods of 0.75701 and 0.73 339 d, or possibly a double-wave variation with a single period of 1.4 668 d. The two periods are found to be coherent over 1.2 yr with no in dication of period changes or amplitude variations, but there is an un explained residual scatter. No additional coherent periodicities are f ound. Significant colour variations, which can be interpreted as tempe rature changes, are present. High-resolution spectroscopic observation s obtained during two nights show distinct line profile changes charac teristic of non-radial pulsation or starspots, but no significant radi al velocity variations. This star may be an example of a new class of pulsating variable.