In this paper, we present the results of a multisite photometric campaign devoted to the γ Doradus type variable HR 8799. From Johnson and Strömgren data, we were able to identify three independent frequencies (f1= 1.9791 cycle d‐1, f2=1.7268 cycle d‐1 and f3=1.6498 cycle d‐1) as well as another signal, which we are able to identify as the coupling term between two of the frequencies (f4=f1‐f2=0.2479 cycle d‐1). These four frequencies are able to account for all of the observed variations down to the 1σ significance level. We discuss another possible interpretation of these frequencies using a model of quasi‐stochastic amplitude modulation. In this scenario, we are able to show that HR 8799 might be pulsating with two independent frequencies, one of which undergoes amplitude modulation similar to other γ Dor objects. In addition, we discuss a preliminary mode identification based on the observed colour curves. Finally, 18 simultaneous, high‐resolution echelle spectra were collected on two nights and we qualitatively compare the radial velocities from these data with our photometry.

No abstract

No abstract

No abstract

A statistical analysis of the period distribution for eclipsing and spectroscopic binary systems, based on the spectral types of the components, shows several common features between the two independent samples. The similarity is increased if the geometrical selection effect on the eclipsing binary sample is eliminated by means of the method described in previous papers. The period distribution becomes broader (and probably nonunimodal) for advanced spectral types. Analysis of the mean separation of systems as a function of the spectral type was also performed