Frequency Analysis of KIC 1573174: Shedding Light on the Nature of HADS Stars

Lv, Chenglong; Esamdin, Ali; Pascual-Granado, J.; Yang, Tao-Zhi; Shen, Dongxiang

doi:10.3847/1538-4357/ac69d9

Cited by 7 publications

(5 citation statements)

References 67 publications

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“…Then a sensible method to model TIC 448892817 is by using Petersen diagrams. Petersen diagrams, therefore, provides a useful diagnostic method in terms of constraining these parameters of radial pulsators (e.g., Petersen 1973;Petersen & Christensen-Dalsgaard 1996;Daszyńska-Daszkiewicz et al 2020;Bowman et al 2021;Lv et al 2022). We provide the best-fitting mass, Z, effective temperature, luminosity, surface gravity, age, theoretical frequency of fundamental, first overtone radial modes, and their ratios listed in Table 4.…”

Section: Stellar Model and Fitting Resultsmentioning

confidence: 99%

“…Advances in sophisticated data processing techniques, such as Lares-Martiz et al (2020), have made possible that frequencies of low amplitude could be found in the spectrum of HADS as well (e.g., Poretti et al 2011;Bowman et al 2021). According to the ratio among the frequencies, the radial modes of HADS could be identified (Petersen 1973), and then by constructing radial frequencies models and comparing the models ratio with the observed ratio, several basic parameters of the star could be obtained, as well as the evolutionary stage (e.g., Xue et al 2018;Bowman et al 2021;Daszyńska-Daszkiewicz et al 2022;Lv et al 2022). A detailed seismic modeling of SX Phe performed by Daszyńska-Daszkiewicz et al (2020), confirmed its post-main-sequence evolutionary stage by using a high-precision photometry collected from TESS mission.…”

Section: Introductionmentioning

confidence: 99%

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Asteroseismology of a Double-mode High-amplitude δ Scuti Star TIC 448892817

Esamdin

Pascual-Granado

et al. 2022

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We propose that TIC 448892817 is a double-mode high-amplitude δ Scuti star. The radial modes detected in this star provide a unique opportunity to exploit asteroseismic techniques up to their limits. 30 significant frequencies are detected by frequency analysis, while two of them are independent frequencies, i.e., F0 = 13.43538(2) day−1 and F1 = 17.27007(4) day−1. The ratio of f 1/f 2 is measured to be 0.777957(2), suggesting that this target is a double-mode δ Scuti star. Nearly all the light variation is due to these two modes and their combination frequencies, but several other frequencies of very low amplitude are also present. The stellar evolutionary models were constructed with different mass M and metallicity Z using Modules for Experiments in Stellar Astrophysics (MESA). The frequency ratio f 1/f 2 obtained by the model is smaller than those obtained by observation. This might be caused by the rotation of the star pointing that rotational effects are more important than previously thought in HADS stars. This is something that deserves to be investigated in future works with models including rotational effects for moderate to intermediate rotators such as FILOU. On the other hand, the parameters obtained from MESA agree well with previous results as well as by observational spectra. The best-fitting model shows that TIC 448892817 is close to entering the first turnoff of the main sequence. In order to accurately determine the effective temperature and metallicities, thus further narrowing the parameter space of this star, we suggest high-resolution spectra is highly desired in the future.

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Section: Stellar Model and Fitting Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Asteroseismology of a Double-mode High-amplitude δ Scuti Star TIC 448892817

Esamdin

Pascual-Granado

et al. 2022

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“…The smaller Galactic Scuti amplitudes, caused by smaller temperature fluctuations lead to a flatter PC relation at maximum light. Hence, we have good support for the HIF stellar photosphere theory as described in Simon et al 1993;Das et al 2020, and references therein. We also note that there is some controversy over the pulsation mode of Scuti stars and in fact whether they may be pulsating in a number of modes and/or have a non-radial component (Netzel et al 2022;Lv et al 2022;Khruslov 2022;Netzel & Smolec 2022). When we cross-checked our sample with the triple mode stars as listed in Netzel et al (2022), we found 32 such stars in our sample.…”

Section: A Possible Theoretical Explanationmentioning

confidence: 90%

Period–colour and amplitude–colour relations for OGLE-δ Scuti stars in the Galactic bulge and LMC

Deka

Deb

Das

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We present an analysis on the behaviour of the Galactic bulge and the Large Magellanic Cloud (LMC) δ Scuti stars in terms of period-colour and amplitude-colour (PCAC) relations at maximum, mean and minimum light. The publicly available Optical Gravitational Lensing Experiment-IV (OGLE-IV) light curves for Galactic bulge and OGLE-III light curves for LMC δ Scuti stars are exploited for the analysis. It has been found that the Galactic bulge δ Scuti stars obey flat PC relations at maximum/mean/minimum light while the LMC δ Scutis have sloped/sloped/flat PC relations at maximum/mean/minimum light. Both the Galactic bulge and the LMC δ Scutis have sloped/flat/sloped AC relations at maximum/mean/minimum. These relations also show that Galactic δ Scutis are hotter as compared to their LMC counterparts. The period-amplitude (PA) relations for δ Scutis exhibit different behaviour in the Galactic bulge and the LMC. The LMC variables are found to have higher amplitudes at a given period. The amplitude of the Galactic bulge δ Scuti shows a bimodal distribution which can be modelled using a two-component Gaussian Mixture Model: one component with a lower amplitude and another with a higher amplitude. The observed behaviour of the δ Scuti PCAC relations can be explained using the theory of the interaction of hydrogen ionization front (HIF) and stellar photosphere as well as the PA diagram. We use MESA-RSP to calculate theoretical non-linear hydrodynamical pulsation models for δ Scuti stars with input metallicities of Z = 0.02 and Z = 0.008 appropriate for the Galactic bulge and LMC, respectively. The observed PCAC relations and theoretical calculations support the HIF-photosphere interaction theory.

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“…A careful examination was performed to select and discard the combination frequencies f c = M f i + L f j , where M and L are integers. In general, the combination frequencies f c have amplitudes much lower than the parent (or independent) frequencies f i and f j (Breger & Lenz 2008;Breger et al 2011;Lv et al 2022), which are more severe in higher-order terms. Pápics (2012) recommended that one should try to find higher-order combinations only when the presence of second-order terms is proven.…”

Section: Identification Of Independent Frequenciesmentioning

confidence: 98%

Asteroseismic Determination of Stellar Rotation: On Synchronization in the Close Eclipsing Binaries AB Cas and OO Dra

Kim

2023

ApJ

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A star’s rotation rate is difficult to estimate without surface inhomogeneities such as dark or bright spots. This paper presents asteroseismic results to determine the rotation rates of δ Sct-type pulsating primary stars in two eclipsing binary systems, AB Cas and OO Dra. After removing the binarity-induced light variations from archival TESS data and carefully examining the combination frequencies, we identified 12 independent frequencies for AB Cas and 11 frequencies for OO Dra, with amplitudes higher than ∼0.3 mmag, as δ Sct-type pulsation frequencies excited in each primary star. The theoretical frequencies for seismic analysis were obtained by fully considering rotation effects. Grid fitting for various stellar properties, such as mass, radius, metallicity, and rotation rate, yielded the best solutions for which the theoretical frequencies and stellar parameters agreed well with the observations. The rotation rate of the AB Cas primary was tightly constrained to 0.81 ± 0.01 day−1 (f rot/f orb = 1.11 − 0.02 + 0.01 ), which is slightly faster than the synchronized rotation. In contrast, the rotation rate of 0.63 ± 0.01 day−1 for the OO Dra primary is lower than the synchronous value of approximately 0.81 day−1. Subsynchronous rotation is uncommon in short-period binaries, and its physical mechanism is not yet well understood. Our results show that asteroseismology can be used to measure the rotation rate of fast-rotating δ Sct stars precisely and thus provide a valuable constraint on rotation–orbit synchronization in close binary systems.

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Frequency Analysis of KIC 1573174: Shedding Light on the Nature of HADS Stars

Cited by 7 publications

References 67 publications

Asteroseismology of a Double-mode High-amplitude δ Scuti Star TIC 448892817

Asteroseismology of a Double-mode High-amplitude δ Scuti Star TIC 448892817

Period–colour and amplitude–colour relations for OGLE-δ Scuti stars in the Galactic bulge and LMC

Asteroseismic Determination of Stellar Rotation: On Synchronization in the Close Eclipsing Binaries AB Cas and OO Dra

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