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| Paper: |
Amplitude Modulation in the ZZ Ceti Star GD 244 |
| Volume: |
493, 19th European Workshop on White Dwarfs |
| Page: |
245 |
| Authors: |
Bognár, Zs.; Paparó, M.; Molnár, L.; Plachy, E.; Sódor, Á. |
| Abstract: |
Previous studies of GD 244 revealed seven pulsation frequencies (two doublets and three single periods) in the light
variations of the star. The data obtained at McDonald Observatory between 2003 and 2006, and our additional
measurements in 2006 and 2007 at Konkoly Observatory, allow the investigation of the long-term pulsational behaviour
of GD 244. We found that the 307.1 s period component of one of the doublets show long-term, periodic amplitude modulation
with a time scale of ∼ 740 days. Possible explanations are that nonlinear resonant mode coupling is operating
among the rotationally split frequency components, or two modes, unresolved in the yearly data are excited at ∼ 307.1 s.
This is the first time that such long-term periodic amplitude modulation is published on a ZZ Ceti star. |
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