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Spectroscopic pulsational frequency identification and mode determination of γ Doradus star HD 135825


E-mail: (EB); (DJW)


We present the mode identification of frequencies found in spectroscopic observations of the γ Doradus star HD 135825. Four frequencies were successfully identified: 1.3150 ± 0.0003, 0.2902 ± 0.0004, 1.4045 ± 0.0005 and 1.8829 ± 0.0005 d−1. These correspond to (l, m) modes of (1, 1), (2, −2), (4, 0) and (1, 1), respectively. Additional frequencies were found but they were below the signal-to-noise ratio limit of the Fourier spectrum and not suitable for mode identification. The rotational axis inclination and v sin i of the star were determined to be 87° (nearly edge-on) and 39.7 km s−1 (moderate for γ Doradus stars), respectively. A simultaneous fit of these four modes to the line profile variations in the data gives a reduced χ2 of 12.7. We confirm, based on the frequencies found, that HD 135825 is a bona fide γ Doradus star.