分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Homogeneous metallicities and continuous high-precision light curves play key roles in studying the pulsation properties of RR Lyrae stars. By cross-matching with LAMOST DR6, we have determined 7 and 50 Non-Blazhko RRab stars in the Kepler and K2 fields, respectively, who have homogeneous metallicities determined from low-resolution spectra of the LAMOST-Kepler/K2 project. The Fourier Decomposition method is applied to the light curves of these stars provided by the Kepler space based telescope to determine the fundamental pulsation periods and the pulsation parameters. The calculated amplitude ratios of R21, R31 and the phase differences of {\phi}21, {\phi}31 are consistent with the parameters of the RRab stars in both the Globular Clusters and the Large Magellanic Cloud. We find a linear relationship between the phase differences {\phi}21 and {\phi}31, which is in good agreement with the results in previous literature. As far as the amplitude, we find that the amplitude of primary frequency A1 and the total amplitude Atot follow either a cubic or linear relationship. For the rise time RT, we do not find its relevance with the period of the fundamental pulsation mode P1, or Atot and {\phi}21. However, it might follow a linear relationship with R31. Based on the homogeneous metallicities, we have derived a new calibration formula for the relationship of period-{\phi}31-[Fe/H], which agrees well with the previous studies.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Homogeneous metallicities and continuous high-precision light curves play key roles in studying the pulsation properties of RR Lyrae stars. By cross-matching with LAMOST DR6, we have determined 7 and 50 Non-Blazhko RRab stars in the Kepler and K2 fields, respectively, who have homogeneous metallicities determined from low-resolution spectra of the LAMOST-Kepler/K2 project. The Fourier Decomposition method is applied to the light curves of these stars provided by the Kepler space based telescope to determine the fundamental pulsation periods and the pulsation parameters. The calculated amplitude ratios of R21, R31 and the phase differences of {\phi}21, {\phi}31 are consistent with the parameters of the RRab stars in both the Globular Clusters and the Large Magellanic Cloud. We find a linear relationship between the phase differences {\phi}21 and {\phi}31, which is in good agreement with the results in previous literature. As far as the amplitude, we find that the amplitude of primary frequency A1 and the total amplitude Atot follow either a cubic or linear relationship. For the rise time RT, we do not find its relevance with the period of the fundamental pulsation mode P1, or Atot and {\phi}21. However, it might follow a linear relationship with R31. Based on the homogeneous metallicities, we have derived a new calibration formula for the relationship of period-{\phi}31-[Fe/H], which agrees well with the previous studies.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Guo-Jie Feng
Ali Esamdin
Jian-Ning Fu
Hu-Biao Niu
Peng Zong
Tao-Zhi Yang
Shu-Guo Ma
Jing Xu
Chun-Hai Bai
Yong Wang
Wei-Chao Sun
Xin-Liang Wang
摘要： KIC 10417986 is a short orbital period (0.0737 d) ellipsoidal variable star with a {\delta} Scuti and {\gamma} Doradus hybrid pulsations component discovered by Kepler. The ground-based spectroscopic observations were carried out in the winters of 2020 and 2021 to investigate the binary nature of this star. We derive the orbital parameters using the rvfit code with a result of K1 = 29.7 $\pm$ 1.5 km/s, {\gamma} = -18.7 $\pm$ 1.7 km/s, and confirm an orbital period of 0.84495 d instead of the result given by Kepler. The atmospheric parameters of the primary are determined by the synthetic spectra fitting technique with the estimated values of Teff = 7411 $\pm$ 187 K, log g = 4.2 $\pm$ 0.3 dex, [M/H] = 0.08 $\pm$ 0.09 dex and vsini = 52 $\pm$ 11 km/s. KIC 10417986 is a circular orbit binary system. From the single-lined nature and mass function of the star, the derived orbital inclination is 26 $\pm$ 6{\deg}, and the mass of the secondary is from 0.43 to 0.7 M_sun, which should be a late-K to early-M type star. Fourteen frequencies are extracted from Kepler light curves, of which six independent frequencies in the high-frequency region are identified as the p-mode pulsations of {\delta} Scuti star, and one independent frequency in the low-frequency region (f2 = 1.3033 c/d) is probably the rotational frequency due to the starspots rather than the ellipsoidal effect or g-mode of {\gamma} Doradus.
点击量
待评议
点击量
下载量
评论
