Bibcode
Solheim, J.-E.; González Pérez, J. M.; Vauclair, G.
Bibliographical reference
Hydrogen-Deficient Stars ASP Conference Series, Vol. 391, proceedings of the conference held 17-21 September, 2007, at Eberhard Karls University, Tübingen, Germany. Edited by Klaus Werner and Thomas Rauch. San Francisco: Astronomical Society of the Pacific, 2008., p.195
Advertised on:
7
2008
Citations
1
Refereed citations
1
Description
We have observed with continuous photometry some hydrogen-deficient
Planetary Nebula Nuclei (PNNs) with bipolar envelopes to search for
pulsations, and to characterize the pulsations found. Our sample
includes the "hybrid PG 1159" stars Abell 43 and NGC 7094 which are
shown to have extremely long period g-mode pulsations between 38 and
101 min, driven by the κ-mechanism. These low amplitude
pulsations were quite stable. We found the PG 1159/E star VV 47 and the
PG 1159/A stars JN 1 and NGC 6852 as highly variable pulsators.
For NGC 246, a PG 1159/lgE object, we observed extremely rapid changes
of pulsation amplitudes and frequencies, apparently with life time of a
few hours. In addition we found a period of 72.5 minutes, which kept its
phase during 3 years, sometimes with a double or triple bumped
pulse-shape. We interpret this as a sign of binarity, indicating a
common envelope surrounding both objects.