Spectroscopic Pulsational Frequency Identification and Mode Determination of Gamma Doradus Star HD135825

TL;DR

This study identifies specific pulsation modes in the Gamma Doradus star HD135825 using spectroscopic data, confirming its classification and providing detailed mode and rotational inclination information.

Contribution

It presents the first spectroscopic mode identification for HD135825, detailing four pulsation modes and star's rotational parameters.

Findings

Four pulsation modes identified: (1,1), (2,-2), (4,0), (1,1).

Star's inclination angle is nearly edge-on at 87 degrees.

Confirmed HD135825 as a Gamma Doradus star.

Abstract

We present the mode identification of frequencies found in spectroscopic observations of the Gamma Doradus star HD135825. Four frequencies were successfully identified: 1.3150 +/- 0.0003 1/d; 0.2902 +/- 0.0004 1/d; 1.4045 +/- 0.0005 1/d; and 1.8829 +/- 0.0005 1/d. 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 limit of the Fourier spectrum and not suitable for mode identification. The rotational axis inclination and vsini of the star were determined to be 87 degrees (nearly edge-on) and 39.7 km/s (moderate for Gamma Doradus stars) respectively. A simultaneous fit of these four modes to the line profile variations in the data gives a reduced chi square of 12.7. We confirm, based on the frequencies found, that HD135825 is a bona fide Gamma Doradus star.