2005/07/20 by T. R. Bedding, L. L. Kiss, H. Kjeldsen +4 · 43 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Envelope (radar) #Excitation #Light curve #Phase (matter) #Physics #Quantum mechanics #Red giant #Solar and Space Plasma Dynamics #Spectral density #Stars #Statistics #Stellar, planetary, and galactic studies #Variable star #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2005.09281.x
published in Monthly Notices of the Royal Astronomical Society 361(4), 1375-1381 (Oxford University Press) · 7 pages, 7 figures, MNRAS in press
arxiv created 2005/07/20 · openalex publication_date 2005/08/03 · arxiv updated 2009/12/01 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05
We analyse visual observations of the pulsations of the red giant variable L2 Puppis (L2 Pup). The data cover 77 yr between 1927 and 2005, thus providing an extensive empirical base for characterizing properties of the oscillations. The power spectrum of the light curve shows a single mode resolved into multiple peaks under a narrow envelope. We argue that this results from stochastic excitation, as seen in solar oscillations, with a mode lifetime of about 5 yr. The random fluctuations in phase also support this idea. A comparison with X Cam, a true Mira star with the same pulsation period, and W Cyg, a true semiregular star, illustrates the basic differences in phase behaviours. The Mira shows very stable phase, consistent with excitation by the κ-mechanism, whereas W Cyg shows large phase fluctuations that imply stochastic excitation. We find L2 Pup to be intermediate, implying that both mechanisms play a role in its pulsation. Finally, we also checked the presence of low-dimensional chaos and could safely exclude it.