The hot Gamma-Doradus and Maia stars


Abstract in English

The hot $gamma$~Doradus stars have multiple low frequencies characteristic of $gamma$~Dor or SPB variables, but are located between the red edge of the SPB and the blue edge of the $gamma$~Dor instability strips where all low-frequency modes are stable in current models of these stars. Though $delta$~Sct stars also have low frequencies, there is no sign of high frequencies in hot $gamma$~Dor stars. We obtained spectra to refine the locations of some of these stars in the H-R diagram and conclude that these are, indeed, anomalous pulsating stars. The Maia variables have multiple high frequencies characteristic of $beta$~Cep and $delta$~Sct stars, but lie between the red edge of the $beta$~Cep and the blue edge of the $delta$~Sct instability strips. We compile a list of all Maia candidates and obtain spectra of two of these stars. Again, it seems likely that these are anomalous pulsating stars which are currently not understood.

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