Kepler and TESS Observations of PG 1159-035

Abstract

PG 1159-035 is the prototype of the DOV hot pre-white dwarf pulsators. It was observed during the Kepler satellite K2 mission for 69 days in 59 s cadence mode and by the TESS satellite for 25 days in 20 s cadence mode. We present a detailed asteroseismic analysis of those data. We identify a total of 107 frequencies representing 32 l=1 modes, 27 frequencies representing 12 l=2 modes, and 8 combination frequencies. The combination frequencies and the modes with very high k values represent new detections. The multiplet structure reveals an average splitting of 4.0+/-0.4 muHz for l=1 and 6.8+/-0.2 muHz for l=2, indicating a rotation period of 1.4+/-0.1 days in the region of period formation. In the Fourier transform of the light curve, we find a significant peak at 8.904+/-0.003 muHz suggesting a surface rotation period of 1.299+/-0.002 days. We also present evidence that the observed periods change on timescales shorter than those predicted by current evolutionary models. Our asteroseismic analysis finds an average period spacing for l=1 of 21.28+/-0.02 s. The l=2 modes have a mean spacing of 12.97+/-0.4 s. We performed a detailed asteroseismic fit by comparing the observed periods with those of evolutionary models. The best fit model has Teff=129600+/- 11100 K, mass M*=0.565+/-0.024 Msun, and log g=7.41+0.38-0.54, within the uncertainties of the spectroscopic determinations. We argue for future improvements in the current models, e.g., on the overshooting in the He-burning stage, as the best-fit model does not predict excitation for all the pulsations detected in PG~1159-03.

27 pages, 9 tables and 26 figures

References in corpus (19)

• The K2 Mission: Characterization and Early results
• A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
• White Dwarf Rotation as a Function of Mass and a Dichotomy of Mode Linewidths: Kepler Observations of 27 Pulsating DA White Dwarfs Through K2 Campaign 8
• A unifying explanation of complex frequency spectra of gamma Dor, SPB and Be stars: combination frequencies and highly non-sinusoidal light curves
• Asteroseismic inferences on GW Vir variable stars in the frame of new PG 1159 evolutionary models
• New nonadiabatic pulsation computations on full PG1159 evolutionary models: the theoretical GW Vir instability strip revisited
• Detection limits for close eclipsing and transiting sub-stellar and planetary companions to white dwarfs in the WASP survey
• The pulsation modes of the pre-white dwarf PG 1159-035
• Asteroseismological measurements on PG 1159-035, the prototype of the GW Vir variable stars
• A deep test of radial differential rotation in a helium-atmosphere white dwarf: I. Discovery of pulsations in PG 0112+104
• Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS: I. Asteroseismology of the GW Vir stars RX J2117+3412, HS 2324+3944, NGC 6905, NGC 1501, NGC 2371, and K 1-16
• The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035
• Evidence of thin helium envelopes in PG1159 stars
• Limits on Mode Coherence in Pulsating DA White Dwarfs Due to a Non-static Convection Zone
• On the robustness of H-deficient post-AGB tracks
• Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with {\it TESS}: III. Asteroseismology of the DBV star GD 358
• Non-local thermodynamic equilibrium spectral analysis of five hot, hydrogen-deficient pre-white dwarfs
• The Missing Link? Discovery of Pulsations in the Nitrogen-rich PG 1159 Star PG 1144+005
• White Dwarf Period Tables - I. Pulsators with hydrogen-dominated atmospheres

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