The Pre-He White Dwarfs in Eclipsing Binaries. II. WASP 0843–11

Hong, Kyeongsoo; Lee, Jae Woo; Koo, Jae‐Rim; Park, Jang-Ho; Rittipruk, Pakakaew; Kim, Hye-Young; Kanjanasakul, Chanisa; Han, Cheongho

doi:10.3847/1538-3881/abdd39

Cited by 10 publications

(6 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…TESS has provided extensive photometric observations of the 200 000 brightest stars in 85% of the sky in the first part of the mission, each observation with a time base of about 27 days per sector observed. In the context of pulsating WDs and pre-WDs, the high-quality observations of TESS, combined with ground-based observations, are able to provide a very important input to the asteroseismology of DBVs (Bell et al 2019;Bognár et al 2021), DAVs (Bognár et al 2020), pre-ELMVs (Wang et al 2020Hong et al 2021), and GW Vir stars (Córsico et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS

Uzundag

Córsico

Althaus

et al. 2021

A&A

View full text Add to dashboard Cite

Context. The Transiting Exoplanet Survey Satellite (TESS) mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus continuing the impulse of its predecessor, the Kepler mission. Aims. In this paper, we present the observations from the extended TESS mission in both 120 s short-cadence and 20 s ultra-short-cadence mode of two pre-white dwarf stars showing hydrogen deficiency. We identify them as two new GW Vir stars, TIC 333432673 and TIC 095332541. We apply the tools of asteroseismology with the aim of deriving their structural parameters and seismological distances. Methods. We carried out a spectroscopic analysis and a spectral fitting of TIC 333432673 and TIC 095332541. We also processed and analyzed the high-precision TESS photometric light curves of the two target stars, and derived their oscillation frequencies. We performed an asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We searched for patterns of uniform period spacings in order to constrain the stellar mass of the stars. We employed the individual observed periods to search for a representative seismological model. Results. The analysis of the TESS light curves of TIC 333432673 and TIC 095332541 reveals the presence of several oscillations with periods ranging from 350 to 500 s associated to typical gravity (g)-modes. From follow-up ground-based spectroscopy, we find that both stars have a similar effective temperature (Teff = 120 000 ± 10 000 K) and surface gravity (log g = 7.5 ± 0.5), but a different He/C composition of their atmosphere. On the basis of PG 1159 evolutionary tracks, we derived a spectroscopic mass of M⋆ = 0.58−0.08+0.16 M⊙ for both stars. Our asteroseismological analysis of TIC 333432673 allowed us to find a constant period spacing compatible with a stellar mass M⋆ ∼ 0.60 − 0.61 M⊙, and an asteroseismological model for this star with a stellar mass M⋆ = 0.589 ± 0.020 M⊙, as well as a seismological distance of d = 459−156+188 pc. For this star, we find an excellent agreement between the different methods to infer the stellar mass, and also between the seismological distance and that measured with Gaia (dGaia = 389−5.2+5.6 pc). For TIC 095332541, we have found a possible period spacing that suggests a stellar mass of M⋆ ∼ 0.55 − 0.57 M⊙. Unfortunately, we have not been able to find an asteroseismological model for this star. Conclusions. Using the high-quality data collected by the TESS space mission and follow-up spectroscopy, we have been able to discover and characterize two new GW Vir stars. The TESS mission is having, and will continue to have, an unprecedented impact on the area of white-dwarf asteroseismology.

show abstract

Section: Introductionmentioning

confidence: 99%

Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS

Uzundag

Córsico

Althaus

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…The two maxima shown at the orbital phases ∼0.25 and ∼0.75, appear to be nearly symmetric. This indicates that any surface inhomogeneity (starspot, Hong et al 2021) or Doppler boosting effect (Prša et al 2016) is negligible. Additionally, the reflection effect due to the hotter star, i.e., brightening around the secondary eclipse, was observed with greater visibility in the shorter wavelength B band.…”

Section: Light Curve Analysismentioning

confidence: 99%

“…More than 15 such samples were discovered using the archival data of the Kepler or TESS space telescopes (Wang et al 2020a). Our group has initiated the spectroscopic follow-up observations of the EL CVn stars to analyze their physical properties more accurately (Lee et al 2020;Hong et al 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Some of these binaries were observed to exhibit multiperiodic pulsations in either one or both the components, i.e., in the A-type primary stars of seven binaries and in the pre-He-WD secondary of five systems (Hong et al 2021). Their stellar properties can be investigated comprehensively through asteroseismological analysis based on the pulsation frequencies (Brown & Gilliland 1994;Aerts 2021).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pulsation and Rotation of the EL CVn-type Eclipsing Binary 1SWASP J024743.37-251549.2

Kim,

Lee,

Lee

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

EL CVn-type eclipsing binaries are composed of a massive A-type main-sequence primary star and a hotter B-type secondary star. This paper presents the time-series photometric and asteroseismic results of the EL CVn-type star 1SWASP J024743.37-251549.2. Well-defined eclipsing light curves were constructed by using the novel high-cadence BV data and archival TESS data, and the physical parameters of each binary component were derived by modeling the light curves. Multiple frequency analysis was performed to investigate the pulsation properties of the binary components. A reliable signal could not be detected in the high-frequency region of 100-300 day −1 , unlike in the previous discovery of three frequencies around 200 day −1 . This indicates that the pulsation amplitudes of the pre-helium white dwarf secondary component decreased considerably. By contrast, 12 frequencies were detected in the range of 33 to 53 day −1 . Most of them were classified as δ Sct-type pulsations originating from the primary star. Theoretical frequencies for the seismic analysis were obtained by adding the non-rotating model frequencies from the GYRE and their rotational shifts from the complete calculation approach. Grid-based fitting was conducted for various stellar properties. The theoretical frequencies and stellar parameters of the best solution concurred well with the observations. The rotation rate was constrained to 1.50 ± 0.02 day −1 , indicating the synchronized rotation of the primary star. The results imply that the complete approach based on the polytropic model is applicable to the seismic analysis of fast-rotating δ Sct stars.

show abstract

“…TESS has provided extensive photometric observations of the 200 000 brightest stars in 85 % of the sky in the first part of the mission, each observation with a time base of about 27 days per sector observed. In the context of pulsating WDs and pre-WDs, the high-quality observations of TESS, combined with ground-based observations, are able to provide a very important input to the asteroseismology of DBVs (Bell et al 2019;Bognár et al 2021), DAVs (Bognár et al 2020), pre-ELMVs (Wang et al 2020;Hong et al 2021), and GW Vir stars (Córsico et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS II. Discovery of two new GW Vir stars: TIC333432673 and TIC095332541

Uzundag,

Córsico,

Kepler

et al. 2021

Preprint

View full text Add to dashboard Cite

Context. The TESS mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus continuing the impulse of its predecessor, the Kepler mission. Aims. In this paper, we present the observations from the extended TESS mission in both 120 s short-cadence and 20 s ultra-shortcadence mode of two pre-white dwarf stars showing hydrogen deficiency. We identify them as two new GW Vir stars, TIC 333432673 and TIC 095332541. We apply the tools of asteroseismology with the aim of deriving their structural parameters and seismological distances. Methods. We carried out a spectroscopic analysis and a spectral fitting of TIC 333432673 and TIC 095332541. We also processed and analyzed the high-precision TESS photometric light curves of the two target stars, and derived their oscillation frequencies. We performed an asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We searched for patterns of uniform period spacings in order to constrain the stellar mass of the stars, and employed the individual observed periods to search for a representative seismological model. Results. The analysis of the TESS light curves of TIC 333432673 and TIC 095332541 reveals the presence of several oscillations with periods ranging from 350 to 500 s associated to typical gravity (g)-modes. From follow-up ground-based spectroscopy, we find that both stars have similar effective temperature (T eff = 120, 000 ± 10, 000 K) and surface gravity (log g = 7.5 ± 0.5) but a different He/C composition of their atmosphere. On the basis of PG 1159 evolutionary tracks, we derived a spectroscopic mass of M ⋆ = 0.58 +0.16 −0.08 M ⊙ for both stars. Our asteroseismological analysis of TIC 333432673 allowed us to find a constant period spacing compatible with a stellar mass M ⋆ ∼ 0.60 − 0.61 M ⊙ , and an asteroseismological model for this star with a stellar mass M ⋆ = 0.589 ± 0.020 M ⊙ , and a seismological distance of d = 459 +188 −156 pc. For this star, we find an excellent agreement between the different methods to infer the stellar mass, and also between the seismological distance and that measured with Gaia (d Gaia = 389 +5.6 −5.2 pc). For TIC 095332541, we have found a possible period spacing that suggests a stellar mass of M ⋆ ∼ 0.55 − 0.57 M ⊙ . Unfortunately, we have not been able to find an asteroseismological model for this star. Conclusions. Using the high-quality data collected by the TESS space mission and follow-up spectroscopy, we have been able to discover and characterize two new GW Vir stars. The TESS mission is having, and will continue to have, an unprecedented impact on the area of white-dwarf asteroseismology.

show abstract

The Pre-He White Dwarfs in Eclipsing Binaries. II. WASP 0843–11

Cited by 10 publications

References 52 publications

Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS

Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS

Pulsation and Rotation of the EL CVn-type Eclipsing Binary 1SWASP J024743.37-251549.2

Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS II. Discovery of two new GW Vir stars: TIC333432673 and TIC095332541

Contact Info

Product

Resources

About