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Paper: Whole Earth Telescope Observations of the ZZ Ceti Star HLTau 76
Volume: 334, 14th European Workshop on White Dwarfs
Page: 477
Authors: Vauclair, G.; WET collaboration
Abstract: This paper analyses the Whole Earth Telescope observations of HL Tau 76 obtained in 1996 and in 1999. In the 1999 data, we find as much as 80 significant frequencies in the power spectrum, of which 33 are independent frequencies after removal of all linear combinations. In taking into account other frequencies present during the 1996 WET campaign and in earlier data, we find a total of 40 independent modes. We use those modes to determine as much as possible of the internal structure of HL Tau 76. The pulsations in HL Tau 76 covers a wide range of periods between 380 s and 1390 s. We propose an identification for many of those modes in terms of l=1 and l=2 nonradial g-modes split by rotation. We derive an average rotation period of 2.2 days. The period distribution of HL Tau 76 is best reproduced if the star has a "thick" hydrogen mass fraction −4.5 ≤ log qH ≤ −4.0. These results have to be confirmed by a detailed comparison of the observed periods with the periods calculated for models as representative as possible of HL Tau 76.
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