2011ApJ...728L..20W

Direct imaging of the HR 8799 system was a major achievement in the study of exoplanets. HR 8799 is a γ Doradus variable and asteroseismology can provide an independent constraint on the inclination. Using 650 high signal-to-noise, high-resolution, full visual wavelength spectroscopic observations obtained over two weeks at Observatoire de Haute Provence with the SOPHIE spectrograph, we find that the main frequency in the radial velocity data is 1.9875/day. This frequency corresponds to the main frequency as found in previous photometric observations. Using the FAMIAS software to identify the pulsation modes, we find that this frequency is a prograde ℓ = 1 sectoral mode and obtain the constraint that inclination i ≳ 40°.