Journal Article

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

E. Brunsden, K. R. Pollard, P. L. Cottrell, D. J. Wright, P. De Cat and P. M. Kilmartin

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 422, issue 4, pages 3535-3545
Published in print June 2012 | ISSN: 0035-8711
Published online May 2012 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2012.20861.x
Spectroscopic pulsational frequency identification and mode determination of γ Doradus star HD 135825

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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.

Keywords: line: profiles; techniques: spectroscopic; stars: individual: HD 135825; stars: oscillations; stars: variables: general

Journal Article.  7514 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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