The Everchanging Pulsating White Dwarf GD358
Abstract
We report 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23rd to June 8th, 2000. We acquired more than 232 000 independent measurements. We also report on 48 hours of time-series photometric observations in Aug 1996. We detected the non-radial g-modes consistent with degree l=1 and radial order 8 to 20 and their linear combinations up to 6th order.We also detect, for the first time, a high amplitude l=2 mode, with a period of 796s. In the 2000 WET data, the largest amplitude modes are similar to those detected with the WET observations of 1990 and 1994, but the highest combination order previously detected was 4th order. At one point during the 1996 observations, most of the pulsation energy was transferred into the radial order k=8 mode, which displayed a sinusoidal pulse shape in spite of the large amplitude. The multiplet structure of the individual modes changes from year to year, and during the 2000 observations only the k=9 mode displays clear normal triplet structure. Even though the pulsation amplitudes change on timescales of days and years, the eigenfrequencies remain essentially the same, showing the stellar structure is not changing on any dynamical timescale.
Cite
@article{arxiv.astro-ph/0301477,
title = {The Everchanging Pulsating White Dwarf GD358},
author = {S. O. Kepler and R. E. Nather and D. E. Winget and A. Nitta and S. J. Kleinman and T. Metcalfe and K. Sekiguchi and J. Xiaojun and D. Sullivan and T. Sullivan and R. Janulis and E. Meistas and R. Kalytis and J. Krzesinski and W. Ogloza and S. Zola and D. O'Donoghue and E. Romero-Colmenero and P. Martinez and S. Dreizler and J. Deetjen and T. Nagel and S. L. Schuh and G. Vauclair and Fu J. Ning and M. Chevreton and J. -E. Solheim and J. M. Gonzalez Perez and F. Johannessen and A. Kanaan and J. E. Costa and A. F. M. Costa and M. A. Wood and N. Silvestri and T. J. Ahrens and A. K. Jones and A. E. Collins and M. Boyer and J. S. Shaw and A. Mukadam and E. W. Klumpe and J. Larrison and S. Kawaler and R. Riddle and A. Ulla and P. Bradley},
journal= {arXiv preprint arXiv:astro-ph/0301477},
year = {2009}
}
Comments
34 pages, 14 figures, WET data, accepted to A&A