HD 219666 b: a hot-Neptune from TESS Sector 1
HD 219666 b: a hot-Neptune from TESS Sector 1
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DOI：
10.1051/0004-6361/201834853
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发表时间：
2018-12
影响因子：
6.5
通讯作者：
M. Esposito;David J Armstrong;D. Gandolfi;V. Adibekyan;M. Fridlund;N. Santos;J. Livingston;E. D. Me
中科院分区：
文献类型：
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作者：
M. Esposito;David J Armstrong;D. Gandolfi;V. Adibekyan;M. Fridlund;N. Santos;J. Livingston;E. D. Me
本文报道了一颗绕旧的静止的G7矮星HD 219666(M⋆=0.92±0.03M⊙，R⋆=1.03±0.03R⊙，τ⋆=10±2Gyr)运行的凌日行星的确证和质量测定。HD 219666 b的质量为Mb=16.6±1.3M⊕，半径为4.71±0.17R⊕，轨道周期为Porb≃6天，是一类罕见的系外行星的新成员。凌日系外行星调查卫星(TESS)在其1区观测到HD 219666(也称为TOI-118)，光曲线显示了四个类似凌日的事件，时间间隔相等。我们用高精度径向速度行星搜索器在ESO3.6m处收集了高精度径向速度测量数据，确认了该候选恒星的行星性质。我们利用高精度径向速度行星搜索器的共加光谱，得到了主星的基本参数(Tef=5527±65K，logg⋆=4.40±0.11(Cgs)，[Fe/H]=0.04±0.04dex，logR‘HK=−5.07±0.03)，以及许多挥发性和难熔元素的丰度。主星的亮度(V=9.9)使其适合于通过凌日光谱进行进一步表征。行星轨道倾角的测定，以及大气层中金属氢含量和热结构的测定，可以为我们提供关于这类天体形成机制的重要线索。
We report on the confirmation and mass determination of a transiting planet orbiting the old and inactive G7 dwarf star HD 219666 (M⋆ = 0.92 ± 0.03 M⊙, R⋆ = 1.03 ± 0.03 R⊙, τ⋆ = 10 ± 2 Gyr). With a mass of Mb = 16.6 ± 1.3 M⊕, a radius of Rb = 4.71 ± 0.17 R⊕, and an orbital period of Porb ≃ 6 days, HD 219666 b is a new member of a rare class of exoplanets: the hot-Neptunes. The Transiting Exoplanet Survey Satellite (TESS) observed HD 219666 (also known as TOI-118) in its Sector 1 and the light curve shows four transit-like events, equally spaced in time. We confirmed the planetary nature of the candidate by gathering precise radial-velocity measurements with the High Accuracy Radial velocity Planet Searcher (HARPS) at ESO 3.6 m. We used the co-added HARPS spectrum to derive the host star fundamental parameters (Teff = 5527 ± 65 K, log g⋆ = 4.40 ± 0.11 (cgs), [Fe/H]= 0.04 ± 0.04 dex, log R′HK = −5.07 ± 0.03), as well as the abundances of many volatile and refractory elements. The host star brightness (V = 9.9) makes it suitable for further characterisation by means of in-transit spectroscopy. The determination of the planet orbital obliquity, along with the atmosphericmetal-to-hydrogen content and thermal structure could provide us with important clues on the formation mechanisms of this class of objects.