A Spectroscopic Analysis of a Sample of K2 Planet-host Stars: Stellar Parameters, Metallicities and Planetary Radii
A Spectroscopic Analysis of a Sample of K2 Planet-host Stars: Stellar Parameters, Metallicities and Planetary Radii
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DOI：
10.3847/1538-4357/acb137
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发表时间：
2023-01
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通讯作者：
V. Loaiza-Tacuri;K. Cunha;V. Smith;C. Martinez;L. Ghezzi;S. Schuler;J. Teske;S. Howell
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作者：
V. Loaiza-Tacuri;K. Cunha;V. Smith;C. Martinez;L. Ghezzi;S. Schuler;J. Teske;S. Howell
凌日系外行星的物理性质与其宿主恒星的物理性质有关。本文基于WIYN望远镜上Hydra摄谱仪观测到的fgk型恒星的光谱进行了均匀光谱分析。我们得到了K2观测到的81颗恒星和开普勒1观测到的33颗恒星的有效温度、表面重力和金属丰度。我们构建了一个足以分析覆盖6050-6350 Å的R ~ 18,000光谱的Fe i和ii线列表，并采用了基于等效宽度测量的光谱技术。计算是在LTE中使用Kurucz模型大气和qoylur -quipu （q2）包完成的。我们通过对基准太阳双胞胎和太阳代理的分析验证了我们的方法，它们被用作太阳参考。我们估计了包括泽曼敏感铁i线在内的影响对我们样本中年轻和可能活跃的恒星的衍生恒星参数的影响，发现它们并不显著。将恒星参数与Gaia EDR3和V星等及等时线相结合，得到了恒星质量和半径。测量到的恒星半径的内部精度中值为4.2%，这导致了推导出的行星半径的内部不确定性中值为4.4%。通过我们的83颗已确认的行星绕K2主星运行的样本，我们发现了R行星（约1.9 R⊕）附近的半径缺口，这与之前的发现一致。行星半径、轨道周期和金属丰度之间的关系被探索，这些也证实了开普勒1系统之前的发现。
The physical properties of transiting exoplanets are connected with the physical properties of their host stars. We present a homogeneous spectroscopic analysis based on the spectra of FGK-type stars observed with the Hydra spectrograph on the WIYN telescope. We derived the effective temperatures, surface gravities, and metallicities, for 81 stars observed by K2 and 33 by Kepler 1. We constructed an Fe i and ii line list that is adequate for the analysis of R ∼ 18,000 spectra covering 6050–6350 Å and adopted the spectroscopic technique based on equivalent-width measurements. The calculations were done in LTE using Kurucz model atmospheres and the qoyllur-quipu (q 2) package. We validated our methodology via an analysis of a benchmark solar twin and solar proxies, which are used as a solar reference. We estimated the effects that including Zeeman-sensitive Fe i lines have on the derived stellar parameters for young and possibly active stars in our sample and found them not to be significant. Stellar masses and radii were derived by combining the stellar parameters with Gaia EDR3 and V magnitudes and isochrones. The measured stellar radii have a 4.2% median internal precision, leading to a median internal uncertainty of 4.4% in the derived planetary radii. With our sample of 83 confirmed planets orbiting K2 host stars, the radius gap near R planet ∼ 1.9 R ⊕ is detected, in agreement with previous findings. Relations between the planetary radius, orbital period, and metallicity are explored and these also confirm previous findings for Kepler 1 systems.