The γ Dor variable HR 8799: Results from a multisite campaign

DOI: 
Publication date: 
01/01/1999
Main author: 
Zerbi F.M.
IAA authors: 
Rodríguez, E.;Garrido, R.;Martín, S.
Authors: 
Zerbi F.M., Rodríguez E., Garrido R., Martín S., Arellano Ferro A., Sareyan J.P., Krisciunas K., Akan M.C., Evren S., Ibanoǧlu C., Keskin V., Pekünlü R., Tunca Z., Luedeke K., Paparó M., Nuspl J., Guerrero G.
Journal: 
Monthly Notices of the Royal Astronomical Society
Publication type: 
Article
Volume: 
303
Pages: 
275-283
Number: 
Abstract: 
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.
Database: 
SCOPUS
Keywords: 
Stars: individual: HR 8799; Stars: oscillations; Stars: variables: other