Continued Period Changes in BW Vulpeculae
Abstract
BW Vulpeculae (BW Vul) has the largest amplitude of the beta Cephei stars. Over almost 80 years of observations, BW Vul has closely followed a parabolic ephemeris and possibly a light-travel-time effect. This parabola, with excursions on either side, also could be viewed as a sequence of straight lines (constant period) with abrupt period increases. This paradigm predicted a period increase around 2004, which did not occur. A recent observing campaign on this star using the AAVSOnet's Bright Star Monitor telescopes as well as the 0.7-m Lowell Observatory telescope has been undertaken. A period analysis of our data suggests that the period may have paradoxically decreased beginning around 2009. Further observations are necessary to confirm this analysis.
- Publication:
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Journal of the American Association of Variable Star Observers (JAAVSO)
- Pub Date:
- June 2020
- Bibcode:
- 2020JAVSO..48...28C