Determination of the Inclination of the Multi-planet Hosting Star HR 8799 Using Asteroseismology

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^-1. 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 ell = 1 sectoral mode and obtain the constraint that inclination i >~ 40°.

Based on observations obtained at the Observatoire de Haute-Provence which is operated by the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France.