PG 1159-035 is the prototype of the PG 1159 hot (pre-)white dwarf pulsators. This important object 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 eight 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 μ Hz for ℓ = 1 and 6.8 ± 0.2 μ Hz 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 μ Hz 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 T eff = 129, 600 ± 11 100 K, M * = 0.565 ± 0.024 M ⊙ , and , 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 of the pulsations detected in PG 1159-035.
Oliveira da Rosa, Gabriela, et al. "Kepler and TESS Observations of PG 1159-035." The Astrophysical Journal, vol. 936, no. 2, Sep. 2022. https://doi.org/10.3847/1538-4357/ac8871
Oliveira da Rosa, Gabriela, Kepler, S. O., Córsico, Alejandro H., Costa, J. E. S., Hermes, J. J., Kawaler, S. D., Bell, Keaton J., Montgomery, M. H., Provencal, J. L., Winget, D. E., Handler, G., Dunlap, Bart, Clemens, J. C., & Uzundag, Murat (2022). Kepler and TESS Observations of PG 1159-035. The Astrophysical Journal, 936(2). https://doi.org/10.3847/1538-4357/ac8871
Oliveira da Rosa, Gabriela, Kepler, S. O., Córsico, Alejandro H., et al., "Kepler and TESS Observations of PG 1159-035," The Astrophysical Journal 936, no. 2 (2022), https://doi.org/10.3847/1538-4357/ac8871
@article{osti_1887325,
author = {Oliveira da Rosa, Gabriela and Kepler, S. O. and Córsico, Alejandro H. and Costa, J. E. S. and Hermes, J. J. and Kawaler, S. D. and Bell, Keaton J. and Montgomery, M. H. and Provencal, J. L. and Winget, D. E. and others},
title = {Kepler and TESS Observations of PG 1159-035},
annote = {Abstract PG 1159-035 is the prototype of the PG 1159 hot (pre-)white dwarf pulsators. This important object 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 eight 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 μ Hz for ℓ = 1 and 6.8 ± 0.2 μ Hz 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 μ Hz 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 T eff = 129, 600 ± 11 100 K, M * = 0.565 ± 0.024 M ⊙ , and log g = 7.41 − 0.54 + 0.38 , 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 of the pulsations detected in PG 1159-035. },
doi = {10.3847/1538-4357/ac8871},
url = {https://www.osti.gov/biblio/1887325},
journal = {The Astrophysical Journal},
issn = {ISSN 0004-637X},
number = {2},
volume = {936},
place = {United States},
publisher = {American Astronomical Society},
year = {2022},
month = {09}}
Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT); Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS); National Aeronautics and Space Administration (NASA); National Council for Scientific and Technological Development (CNPq); National Science Centre (NCN); National Science Foundation (NSF); USDOE; USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
NA0003843; SC0010623
OSTI ID:
1887325
Alternate ID(s):
OSTI ID: 1981267
Journal Information:
The Astrophysical Journal, Journal Name: The Astrophysical Journal Journal Issue: 2 Vol. 936; ISSN 0004-637X