2011/02/28 by Daniel Huber, Timothy R. Bedding, T. R. Bedding +16 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/731/2/94
10 pages, 9 figures, accepted for publication in ApJ; v2 includes minor changes made in the proofs (updated references & corrected typos)
arxiv created 2011/03/09 · openalex publication_date 2011/03/29 · arxiv updated 2015/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
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 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 l =0,phot / A l =0,RV = 0.24 ± 0.02 ppm cm −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.