RAPID EVOLUTION OF GSC 03144-595, a NEW TRIPLE-MODE RADIALLY PULSATING HIGH-AMPLITUDE Δ SCUTI

Mow, Benjamin; Reinhart, Erik D.; Nhim, Samantha; Watkins, Richard

doi:10.3847/0004-6256/152/1/17

“…The results of the seismic models re-confirm the conclusion that f 0 , f 1 , and f 2 are the fundamental, first overtone, and second overtone radial p-modes, respectively [11]. Moreover, it shows that this star locates in the later evolutionary phase of the Hertzsprung gap, which is a more rapidly evolving phase compared with those stars in the earlier evolutionary phase of the Hertzsprung gap (such as AE UMa [5] and VX Hya [6]).…”

Section: Main Bodysupporting

confidence: 71%

“…KIC6382916 (J19480292+4146558, also known as GSC 03144-595) is a HADS to be monitored extensively by the Kepler space telescope for its pulsation properties, which shows three independent frequencies (pulsation modes) in its light curves [10]. These three pulsation modes have been confirmed as the fundamental, the first overtone and the second overtone radial p-modes [11], and T eff = 6950 ± 100 K, log g = 3.7 ± 0.1 and v sin i = 50 ± 10 km s −1 have been estimated by the high-dispersion spectra [10]. [6,12,13], the variations of the frequencies can be derived from the variations of the phases.…”

Section: Main Bodymentioning

confidence: 99%

A rapidly evolving high-amplitude δ Scuti star crossing the Hertzsprung Gap

Niu

¹

,

Xue

²

2021

Preprint

0

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People cannot witness the stellar evolution process of a single star obviously in most cases because of its extremely secular time-scale, except for some special time nodes in it (such as the supernova explosion [1]). But in some specific evolutionary phases, we have the chances to witness such process gradually on human times-scales. When a star evolved leaving from the main sequence, the hydrogen nuclei fusion in its core is gradually transferring into the shell. In the Hertzsprung–Russell diagram, its evolutionary phase falls into the Hertzsprung gap, which is one of the most rapidly evolving phases in the life of a star [2]. Here we report a discovery of a rapidly evolving high-amplitude δ Scuti star KIC6382916 (J19480292+4146558) which is crossing the Hertzsprung gap. According to the analysis of the archival data, we find three independent pulsation modes of it, whose amplitudes and frequencies are variating distinctly in 4 years. The period variation rates of the three pulsation modes are one or two orders larger than the best seismic model constructed by the standard evolution theory, which indicates the current theory cannot precisely describe the evolution process in this rapidly evolving phase and needs further upgrades. Moreover, the frequency and amplitude interactions between the three independent pulsation modes and their harmonics/combinations open a new window to the future asteroseismology.

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“…KIC6382916 (J19480292+4146558, also known as GSC 03144-595) is a HADS to be monitored extensively by the Kepler space telescope for its pulsation properties, which shows three independent frequencies (pulsation modes) in its light curves (Ulusoy et al 2013). These three pulsation modes have been confirmed as the fundamental, the first overtone and the second overtone radial p-modes (Mow et al 2016), and T eff = 6950 ± 100 K, log g = 3.7 ± 0.1 and v sin i = 50 ± 10 km s −1 have been estimated by the high-dispersion spectra (Ulusoy et al 2013). Using the long-cadence (LC) photometric data of KIC6382916 lasted from BJD 2454953 to 2456424 (Quarter 0-17), we extract the first 23 frequencies with largest amplitudes (which have a cut-off of 1.3 mmag, see in Table 2 for more details) to study the variations and interactions of them.…”

mentioning

confidence: 76%

“…tively (Mow et al 2016). Moreover, it shows that this star locates in the later evolutionary phase of the Hertzsprung gap, which is a more rapidly evolving phase compared with those stars in the earlier evolutionary phase of the Hertzsprung gap (such as AE UMa (Niu et al 2017) and VX Hya (Xue et al 2018)).…”

mentioning

confidence: 99%

A rapidly evolving high-amplitude $δ$ Scuti star crossing the Hertzsprung Gap

Niu¹,

Xue²

2021

Preprint

View full text Add to dashboard Cite

People cannot witness the stellar evolution process of a single star obviously in most cases because of its extremely secular time-scale, except for some special time nodes in it (such as the supernova explosion). But in some specific evolutionary phases, we have the chances to witness such process gradually on human times-scales. When a star evolved leaving from the main sequence, the hydrogen nuclei fusion in its core is gradually transferring into the shell. In the Hertzsprung-Russell diagram, its evolutionary phase falls into the Hertzsprung gap, which is one of the most rapidly evolving phases in the life of a star. Here we report a discovery of a rapidly evolving high-amplitude δ Scuti star KIC6382916 (J19480292+4146558) which is crossing the Hertzsprung gap. According to the analysis of the archival data, we find three independent pulsation modes of it, whose amplitudes and frequencies are variating distinctly in 4 years. The period variation rates of the three pulsation modes are one or two orders larger than the best seismic model constructed by the standard evolution theory, which indicates the current theory cannot precisely describe the evolution process in this rapidly evolving phase and needs further upgrades. Moreover, the newly introduced Interaction Diagram can help us to find the interactions between the three independent pulsation modes and their harmonics/combinations, which opens a new window to the future asteroseismology. MAIN BODYδ Scuti stars are a class of short-period pulsating variable stars with period between 0.02 and 0.25 day and the spectral classes A-F, which locate on the main sequence or post main sequence evolutionary stage at the bottom of the classical Cepheid instability strip and excited by the κ mechanism (Breger 2000). High-amplitude δ Scuti stars (hereafter HADS) are a subclass of δ Scuti stars, who always have larger amplitudes (∆V ≥ 0 m. 3) and slower rotations (Breger 2000). Most of the HADS show single or double radial pulsation modes, and some of them have three radial pulsation modes or even some non-radial pulsation modes (Niu et al. 2013(Niu et al. , 2017Xue et al. 2018;Wils et al. 2008). Theoretically, the period variation rates ((1/P )( dP/ dt)) of HADS caused by the evolution should have a value from 10 −10 yr −1 on the main sequence to 10 −7 yr −1 on the post-main sequence phase (Breger & Pamyatnykh 1998). According to the seismic models, the observed period variation

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“…Only five HADS stars with three consecutive radial modes, i.e. AC And (Fitch & Szeidl 1976), V823 Cas (Jurcsik et al 2006), V829 Aql (Handler et al 1998), GSC 762-110 (Wils et al 2008) and GSC 03144-595 (Mow et al 2016), are found at present.…”

Section: Introductionmentioning

confidence: 90%

KIC 10975348: A Double-mode or Triple-mode High-amplitude δ Scuti Star?

Yang

¹

,

Sun

²

,

Zuo

³

et al. 2020

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In this paper, we analyze the light variations of KIC 10975348 using photometric data delivered from the Kepler mission. This star is exceptionally faint (K p = 18.6 mag) compared to most well-studied δ Scuti stars. The Fourier analysis of the short-cadence data (i.e., Q14, Q15, and Q16, spanning 220 days) reveals that the variations are dominated by the strongest mode with a frequency of F0 = 10.231899 day−1, which is compatible with that obtained from RATS–Kepler. The other two independent modes with F1 (=13.4988 day−1) and F2 (=19.0002 day−1) are newly detected and have amplitudes two orders of magnitude smaller than F0. We note that, for the first time, this star is identified to be a high-amplitude δ Sct (HADS) star with an amplitude of about 0.7 mag, and the lower ratio of F0/F1 = 0.758 suggests that it might be a metal-rich variable star. The frequency F2 may be a third overtone mode, suggesting that this target might be a new radial triple-mode HADS star. We perform an O − C analysis using 1018 newly determined times of maximum light and derive an ephemeris formula of T max = 2456170.241912(0)+0.097734(1) × E. The O − C diagram shows that the pulsation period of KIC 10975348 seems to show no obvious change, which is in contrast to that of the majority of HADS stars. The possible cause of that may be due to the current short time span of the observations. To verify its possible period variations, regular observation from space with a longer time span in the future is needed.

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RAPID EVOLUTION OF GSC 03144-595, a NEW TRIPLE-MODE RADIALLY PULSATING HIGH-AMPLITUDE Δ SCUTI

Cited by 14 publications

References 19 publications

A rapidly evolving high-amplitude δ Scuti star crossing the Hertzsprung Gap

A rapidly evolving high-amplitude δ Scuti star crossing the Hertzsprung Gap

A rapidly evolving high-amplitude $δ$ Scuti star crossing the Hertzsprung Gap

KIC 10975348: A Double-mode or Triple-mode High-amplitude δ Scuti Star?

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