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تسجيل مستخدم جديدAsteroseismology of RRab variable star EZ Cnc from K2 photometry and LAMOST spectroscopy
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EZ Cnc, or EPIC 212182292, is a non-Blazhko RRab variable star located in the field of K2 Campaign 16. Its atmospheric parameters ($T_{rm eff}$, $log{g}$, [M/H]) and radial velocities are measured from the 55 high-quality LAMOST medium-resolution spectra. The fundamental frequency of pulsation is derived as $f=1.8323(17)$ d$^{-1}$ from the K2 light curves. The amplitude ratios $R_{21} = 0.5115(15), 0.490(8)$, $R_{31} = 0.3249(20), 0.279(7)$ and Fourier phase differences $varphi_{21}=2.7550(20), 2.764(16)$, $varphi_{31}=5.7194(25), 5.719(31)$ are determined from the Fourier decomposition of K2 light curve and LAMOST radial velocity curve, respectively. Through the constraints of the parameters, four optimal models are obtained in a time-dependent turbulent convection model survey for EPIC 212182292. The parameters of EPIC 212182292 are derived as $M=0.48pm0.03$ M$_{odot}$, $L = 42pm2$ L$_{odot}$, $T_{rm eff}=6846pm50$ K, $log{g}=2.79pm0.01$ dex, and $Z = 0.006pm0.002$, respectively. The precisely determined parameters for RRab variable stars like EPIC 212180092 might help to better understand the period-luminosity relationship of RR Lyrae stars.
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