On ɛ-mechanism-driven pulsations in VV 47

Sowicka, P.; Handler, G.; Jones, D.
Referencia bibliográfica

Monthly Notices of the Royal Astronomical Society, Volume 479, Issue 2, p.2476-2480

Fecha de publicación:
9
2018
Descripción
We report new observations of the central star of the planetary nebula VV 47 carried out to verify earlier assertions that the short-period pulsation modes detected in the star are driven by the ɛ-mechanism. In our data, VV 47 was not variable up to a limit of 0.52 mmag in the Fourier amplitude spectrum up to the Nyquist frequency of 21.7 mHz. Given this null result we re-analysed the data set in which oscillations were claimed. After careful data reduction, photometry, extinction correction, and analysis with a conservative criterion of S/N ≥ 4 in the Fourier amplitude spectrum, we found that the star was not variable during the original observations. The oscillations reported earlier were due to an over-optimistic detection criterion. We conclude that VV 47 did not pulsate during any measurements at hand; the observational detection of ɛ-driven pulsations remains arduous.
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