SOLAR-LIKE OSCILLATIONS AND ACTIVITY IN PROCYON: A COMPARISON OF THE 2007 MOST AND GROUND-BASED RADIAL VELOCITY CAMPAIGNS
- Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia)
- Danish AsteroSeismology Centre (DASC), Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)
- Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Marys University, NS B3H 3C3, Halifax (Canada)
- University of Vienna, Institute for Astronomy, 1180 Vienna (Austria)
We compare the simultaneous 2007 space-based MOST photometry and ground-based radial velocity (RV) observations of the F5 star Procyon. We identify slow variations in the MOST data that are similar to those reported in the RV time series and confirm by comparison with the Sun that these variations are likely the signature of stellar activity. The MOST power spectrum yields clear evidence for individual oscillation frequencies that match those found in the RV data by Bedding et al. We identify the same ridges due to modes of different spherical degree in both data sets, but are not able to confirm a definite ridge identification using the MOST data. We measure the luminosity amplitude per radial mode A{sub l=0,phot} = 9.1 {+-} 0.5 ppm. Combined with the estimate for the RV data by Arentoft et al., this gives a mean amplitude ratio of A{sub l=0,phot}/A{sub l=0,RV} = 0.24 {+-} 0.02 ppm cm{sup -1} s, considerably higher than expected from scaling relations but in reasonable agreement with theoretical models by Houdek. We also compare the amplitude ratio as a function of frequency and find that the maximum of the oscillation envelope is shifted to higher frequencies in photometry than in velocity.
- OSTI ID:
- 21574711
- Journal Information:
- Astrophysical Journal, Vol. 731, Issue 2; Other Information: DOI: 10.1088/0004-637X/731/2/94; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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