Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with {\it TESS}: III. Asteroseismology of the DBV star GD 358

Abstract

The collection of high-quality photometric data by space telescopes is revolutionizing the area of white-dwarf asteroseismology. Among the different kinds of pulsating white dwarfs, there are those that have He-rich atmospheres, and they are called DBVs or V777 Her variable stars. The archetype of these pulsating white dwarfs, GD~358, is the focus of the present paper. We report a thorough asteroseismological analysis of the DBV star GD~358 (TIC~219074038) based on new high-precision photometric data gathered by the {\it TESS} space mission combined with data taken from the Earth. In total, we detected 26 periodicities from the {\it TESS} light curve of this DBV star using a standard pre-whitening. The oscillation frequencies are associated with nonradial $g$(gravity)-mode pulsations with periods from $\sim 422$ s to $\sim 1087$ s. Moreover, we detected 8 combination frequencies between $\sim 543$ s and $\sim 295$ s. We combined these data with a huge amount of observations from the ground. We found a constant period spacing of $39.25\pm 0.17$ s, which helped us to infer its mass ($M_{\star}= 0.588\pm0.024 M_{\sun}$) and constrain the harmonic degree $\ell$ of the modes. We carried out a period-fit analysis on GD~358, and we were successful in finding an asteroseismological model with a stellar mass ($M_{\star}= 0.584^{+0.025}_{-0.019} M_{\sun}$), in line with the spectroscopic mass ($M_{\star}= 0.560\pm0.028 M_{\sun}$). We found that the frequency splittings vary according to the radial order of the modes, suggesting differential rotation. Obtaining a seismological made it possible to estimate the seismological distance ($d_{\mathrm{seis}}=42.85\pm 0.73$ pc) of GD~358, which is in very good accordance with the precise astrometric distance measured by {\it GAIA} EDR3 ($\pi =23.244\pm 0.024,d_{\mathrm{GAIA}}=43.02\pm 0.04$~pc).

15 pages, 10 figures, 5 tables. To be published in Astronomy and Astrophysics. arXiv admin note: text overlap with arXiv:2011.03629

References in corpus (20)

• The Transiting Exoplanet Survey Satellite
• The K2 Mission: Characterization and Early results
• Pulsating White Dwarf Stars and Precision Asteroseismology
• New white dwarf stars in the Sloan Digital Sky Survey Data Release 10
• 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
• White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 14
• Asteroseismic inferences on GW Vir variable stars in the frame of new PG 1159 evolutionary models
• Measurements of Physical Parameters of White Dwarfs: A Test of the Mass-Radius Relation
• New nonadiabatic pulsation computations on full PG1159 evolutionary models: the theoretical GW Vir instability strip revisited
• Constraining the neutrino magnetic dipole moment from white dwarf pulsations
• A deep test of radial differential rotation in a helium-atmosphere white dwarf: I. Discovery of pulsations in PG 0112+104
• TESS first look at evolved compact pulsators: asteroseismology of the pulsating helium-atmosphere white dwarf TIC 257459955
• 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
• Destroying Aliases from the Ground and Space: Super-Nyquist ZZ Cetis in K2 Long Cadence Data
• Revealing the pulsational properties of the V777 Her star KUV 05134+2605 by its long-term monitoring
• Limits on Mode Coherence in Pulsating DA White Dwarfs Due to a Non-static Convection Zone
• Atmospheric parameters and carbon abundance for hot DB white dwarfs
• EPIC 228782059: Asteroseismology of what could be the coolest pulsating helium-atmosphere white dwarf (DBV) known?
• On the systematics of asteroseismological mass determinations of PG1159 stars
• Identification of White Dwarf from Gaia EDR3 via Spectra from LAMOST DR7

Cited by in corpus (7)

• Kepler and TESS Observations of PG 1159-035
• Pulsating H-deficient WDs and pre-WDs observed with TESS: V. Discovery of two new DBV pulsators, WD J152738.4-450207.4 and WD 1708-871, and asteroseismology of the already known DBV stars PG 1351+489, EC 20058-5234, and EC 04207-4748
• Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS -- IV. Discovery of two new GW Vir stars: TIC0403800675 and TIC1989122424
• Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS VI. Asteroseismology of the GW Vir-type central star of the Planetary Nebula NGC 246
• MOCKA -- A PLATO mock asteroseismic catalogue: Simulations for gravity-mode oscillators
• Exploring the internal rotation of the extremely low-mass He-core white dwarf GD 278 with TESS asteroseismology
• Magnetic dynamos powered by white dwarf superficial convection