PG 1351+489 is one of the 20 DBVs - pulsating helium-atmosphere white dwarf stars - known and has the simplest power spectrum for this class of star, making it a good candidate to study cooling rates. We report accurate period determinations for the main peak at 489.33448s and two other normal modes using data from the Whole Earth Telescope (WET) observations of 1995 and 2009. In 2009, we detected a new pulsation mode and the main pulsation mode exhibited substantial change in its amplitude compared to all previous observations. We were able to estimate the star's rotation period, of 8.9h, and discuss a possible determination of the rate of period change of (2.0 ± 0.9) × 10-13ss -1, the first such estimate for a DBV.


Physics, Astronomy, and Materials Science

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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2011 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.


Stars: evolution, Stars: individual: PG 1351+489, Stars: oscillations, White dwarfs

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Monthly Notices of the Royal Astronomical Society