TESS first look at evolved compact pulsators: asteroseismology of the pulsating helium-atmosphere white dwarf TIC 257459955

Abstract

Pulsation frequencies reveal the interior structures of white dwarf stars, shedding light on the properties of these compact objects that represent the final evolutionary stage of most stars. Two-minute cadence photometry from TESS will record pulsation signatures from bright white dwarfs over the entire sky. We aim to demonstrate the sensitivity of TESS data to measuring pulsations of helium-atmosphere white dwarfs in the DBV instability strip, and what asteroseismic analysis of these measurements can constrain about their stellar structures. We present a case study of the pulsating DBV WD 0158$-$160 that was observed as TIC 257459955 with the 2-minute cadence for 20.3 days in TESS Sector 3. We measure the frequencies of variability of TIC 257459955 with an iterative periodogram and prewhitening procedure. The measured frequencies are compared to calculations from two sets of white dwarf models to constrain the stellar parameters: the fully evolutionary models from LPCODE, and the structural models from WDEC. We detect and measure the frequencies of nine pulsation modes and eleven combination frequencies of WD 0158$-$160 to $\sim 0.01\mu$Hz precision. Most, if not all, of the observed pulsations belong to an incomplete sequence of dipole ($\ell =1$) modes with a mean period spacing of $38.1\pm 1.0$ s. The global best-fit seismic models from both codes have effective temperatures that are $\gtrsim 3000$ K hotter than archival spectroscopic values of $24,100-25,500$ K; however, cooler secondary solutions are found that are consistent with both the spectroscopic effective temperature and distance constraints from Gaia astrometry.

13 pages, 12 figures, accepted for publication in A&A. The abstract reproduced here has been shorted to meet arXiv's character limit

References in corpus (11)

• The Gaia mission
• Pulsating White Dwarf Stars and Precision Asteroseismology
• 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
• A detection threshold in the amplitude spectra calculated from Kepler data obtained during K2 mission
• 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
• Asteroseismological constraints on the coolest GW Vir variable star (PG 1159-type)PG 0122+200
• TESS first look at evolved compact pulsators : Discovery and asteroseismic probing of the g-mode hot B subdwarf pulsator EC 21494-7018
• Revealing the pulsational properties of the V777 Her star KUV 05134+2605 by its long-term monitoring

Cited by in corpus (18)

• A 20-Second Cadence View of Solar-Type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Re-characterization of pi Men c
• Recurring Planetary Debris Transits and Circumstellar Gas around White Dwarf ZTF J0328$-$1219
• Discovery of 74 new bright ZZ Ceti stars in the first three years of TESS
• Carbon-Oxygen Phase Separation in MESA White Dwarf Models
• 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
• On The Impact Of 22Ne On The Pulsation Periods Of Carbon-Oxygen White Dwarfs With Helium Dominated Atmospheres
• Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with {\it TESS}: III. Asteroseismology of the DBV star GD 358
• 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
• The Pulsating Helium-Atmosphere White Dwarfs I: New DBVs from the Sloan Digital Sky Survey
• ZZ Ceti stars of the southern ecliptic hemisphere re-observed by TESS
• 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
• The TESS Mission Target Selection Procedure
• Optical detection of the 1.1-day variability at the white dwarf GD 394 with TESS
• Exploring the pulsational properties of two ZZ Ceti stars
• 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
• GD 99: Re-investigation of an old ZZ Ceti companion
• Asteroseismology of the ZZ Ceti star WD 1310+583 using the Transiting Exoplanet Survey Satellite