Multimode pulsation of the ZZ Ceti star GD 154

M. Paparó, Zs Bognár, E. Plachy, L. Molnár, P. A. Bradley

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

We present the results of a comparative period search on different time-scales and modelling of the ZZ Ceti (DAV) star GD 154. We determined six frequencies as normal modes and four rotational doublets around the ones having the largest amplitude. Two normal modes at 807.62 and 861.56 μHz have never been reported before. A rigorous test revealed remarkable intrinsic amplitude variability of frequencies at 839.14 and 861.56 μHz over a 50 d time-scale.In addition, the multimode pulsation changed to monoperiodic pulsation with an 843.15 μHz dominant frequency at the end of the observing run. The 2.76 μHz average rotational split detected led to a determination of a 2.1 d rotational period for GD 154.We searched for modelsolutions with effective temperatures and log g close to the spectroscopically determined ones.The best-fitting models resulting from the grid search have MH between 6.3 × 10-5 and 6.3 × 10-7M*, which means thicker hydrogen layer than the previous studies suggested. Our investigations show that mode trapping does not necessarily operate in all of the observedmodes and the best candidate for a trapped mode is at 2484 μHz.

Original languageEnglish
Pages (from-to)598-608
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume432
Issue number1
DOIs
Publication statusPublished - Jun 2013

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timescale
stars
trapping
hydrogen
modeling
temperature
grids
test

Keywords

  • Stars:individual:GD 154
  • Stars:interiors
  • Stars:oscillations
  • Techniques:photometric
  • White dwarfs

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Multimode pulsation of the ZZ Ceti star GD 154. / Paparó, M.; Bognár, Zs; Plachy, E.; Molnár, L.; Bradley, P. A.

In: Monthly Notices of the Royal Astronomical Society, Vol. 432, No. 1, 06.2013, p. 598-608.

Research output: Contribution to journalArticle

Paparó, M. ; Bognár, Zs ; Plachy, E. ; Molnár, L. ; Bradley, P. A. / Multimode pulsation of the ZZ Ceti star GD 154. In: Monthly Notices of the Royal Astronomical Society. 2013 ; Vol. 432, No. 1. pp. 598-608.
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