2014/05/27 by John R. Percy, Percy, John R., Rufina Y. H. Kim +2 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #FOS: Physical sciences #History and Developments in Astronomy #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.1405.6993
To be submitted to JAAVSO
openalex publication_date 2014/05/27 · arxiv created 2014/05/29 · arxiv updated 2014/05/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It was recently discovered that the amplitudes of pulsating red giants and supergiants vary significantly on time scales of 20-30 pulsation periods. Here, we analyze the amplitude variability in 29 pulsating yellow supergiants (5 RVa, 4 RVb, 9 SRd, 7 long-period Cepheid, and 4 yellow hypergiant stars), using visual observations from the AAVSO International Database, and Fourier and wavelet analysis using the AAVSO's VSTAR package. We find that these stars vary in amplitude by factors of up to 10 or more (but more typically 3-5), on a mean time scale (L) of 33 +/- 4 pulsation periods (P). Each of the five sub-types shows this same behavior, which is very similar to that of the pulsating red giants, for which the median L/P was 31. For the RVb stars, the lengths of the cycles of amplitude variability are the same as the long secondary periods, to within the uncertainty of each.