Period variation of the classical Cepheid SV Vulpeculae over a century 1913-2022

Period variation of the classical Cepheid SV Vulpeculae over a century 1913-2022 by Guy Boistel. on Tuesday 29 November This study analyzes 338 new times of visual, CCD, photoelectric and photographic maxima of the classical Cepheid SV Vul. The corresponding observations were made between 1913 and 2022. On this new and large observational basis, the period variations of this star of major astrophysical interest are re-visited. Without contradicting the theory or previous studies, we show that visual observations are important for a long-term monitoring of the period variations of well-selected bright Cepheids. This study establishes the period rate of change of SV Vul at -250 s/yr. Its period is currently shorter than 45 days. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16025v1