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arXiv · 2108.02912

OO Dra: an Algol-type binary formed through an extremely helium-poor mass accretion revealed by asteroseismology

Xinghao Chen·Xiaobin Zhang·Yan Li·Changqing Luo·Xuzhi Li·Jie Su·Xuefei Chen
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Abstract

Based on the two-minutes TESS data, we analyzed intrinsic oscillations of the primary component and identified seven confident independent $\delta$ Scuti frequencies ($f_1$, $f_2$, $f_3$, $f_4$, $f_7$, $f_{11}$, and $f_{12}$). Both of single-star evolutionary models and mass-accreting models are computed to reproduce the $\delta$ Scuti freqiencies. Fitting results of them match well with each other. The stellar parameters of the primary star yielded by asteroseismology are $M$ = $1.92^{+0.10}_{-0.02}$ $M_{\odot}$, $Z$ = 0.011$^{+0.006}_{-0.001}$, $R$ = $2.068^{+0.050}_{-0.007}$ $R_{\odot}$, $\log g$ = $4.090^{+0.010}_{-0.002}$, $T_{\rm eff}$ = $8346^{+244}_{-320}$ K, $L$ = $18.65^{+3.31}_{-2.82}$ $L_{\odot}$, which match well with the dynamic ones by the binary model. Furthermore, our asteroseismic results show that OO Dra is another Algol system that has just undergone the rapid mass-transfer stage. Fitting results of single-star evlutionary models indicate that the pulsator is helium-poor star with an age of 8.22$^{+0.12}_{-1.33}$ Myr, and the further mass-accreting models show that the primary star looks like an almost unevolved star formed by an extremely helium-poor mass accretion in Case A evolutionary scenario.

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Xinghao Chen, Xiaobin Zhang, Yan Li, Changqing Luo, Xuzhi Li, Jie Su, Xuefei Chen. 2021-08-06. OO Dra: an Algol-type binary formed through an extremely helium-poor mass accretion revealed by asteroseismology. https://doi.org/10.3847/1538-4357%2Fac1baa

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