The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima - Fundamental parameters from PIONIER, NACO, and UVES observations
The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima - Fundamental parameters from PIONIER, NACO, and UVES observations
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红矮星对 GJ65 AB：比邻星的膨胀、旋转双胞胎 - 来自 PIONIER、NACO 和 UVES 观测的基本参数
DOI：
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
J. L. Bouquin
中科院分区：
文献类型：
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作者：
P. Kervella;A. Mérand;C. Ledoux;B. Demory;J. L. Bouquin
附近的红矮星双星GJ65 AB （UV+BL Ceti, M5.5Ve+M6Ve）是探索极低质量恒星物理学的基石系统。然而，这两颗恒星的半径目前只能从间接的光度估计中得知，这使我们无法使用GJ65 AB作为质量半径（M-R）关系的校准器。本文利用VLTI/PIONIER仪器在近红外H波段对GJ65两组分的角直径进行了新的干涉测量：θUD(A) = 0.558±0.008±0.020 mas, θUD(B) = 0.539±0.009±0.020 mas。θLD(A) = 0.573±0.021 mas, θLD(B) = 0.554±0.022 mas。在已知视差的基础上，直线半径为R(A) = 0.165±0.006 R⊙，R(B) = 0.159±0.006 R⊙(σ(R) /R = 4%)。我们在干涉测量可见性和关闭阶段寻找耀斑和微弱伴星的特征，但我们没有发现任何重要信号。我们还利用VLT/NACO自适应光学系统对GJ65进行了观测，并改进了系统的轨道参数和红外星等。我们推导出m(A) = 0.1225±0.0043 m⊙和m(B) = 0.1195±0.0043 m⊙的两个分量的质量（σ(m) /m = 4%）。为了推导出这两颗恒星的径向速度和旋转速度，以及它们相对于比邻星的金属丰度，我们还提供了这两颗恒星的新的单独的UVES高分辨率光谱。将GJ65 A和B放在质量半径图中，表明它们的半径分别超出了最近模型的预期14±4%和12±4%。根据先前的理论，我们提出这种差异是由于这两颗快速旋转的恒星的发电机效应产生的强内部磁场抑制了对流能输运造成的。与几乎相同的双星比邻星相比，比邻星旋转缓慢，这加强了这一假设，因为比邻星的半径与模型相比似乎没有膨胀。
The nearby red dwarf binary GJ65 AB (UV+BL Ceti, M5.5Ve+M6Ve) is a cornerstone system to probe the physics of very low-mass stars. The radii of the two stars are currently known only from indirect photometric estimates, however, and this prevents us from using GJ65 AB as calibrators for the mass-radius (M–R) relation. We present new interferometric measurements of the angular diameters of the two components of GJ65 with the VLTI/PIONIER instrument in the near-infrared H band: θUD(A) = 0.558 ± 0.008 ± 0.020 mas and θUD(B) = 0.539 ± 0.009 ± 0.020 mas. They translate into limb-darkened angular diameters of θLD(A) = 0.573 ± 0.021 mas and θLD(B) = 0.554 ± 0.022 mas. Based on the known parallax, the linear radii are R(A) = 0.165 ± 0.006 R⊙ and R(B) = 0.159 ± 0.006 R⊙ (σ(R) /R = 4%). We searched for the signature of flares and faint companions in the interferometric visibilities and closure phases, but we did not identify any significant signal. We also observed GJ65 with the VLT/NACO adaptive optics and refined the orbital parameters and infrared magnitudes of the system. We derived masses for the two components of m(A) = 0.1225 ± 0.0043 M⊙ and m(B) = 0.1195 ± 0.0043 M⊙ (σ(m) /m = 4%). To derive the radial and rotational velocities of the two stars as well as their relative metallicity with respect to Proxima, we also present new individual UVES high-resolution spectra of the two components. Placing GJ65 A and B in the mass-radius diagram shows that their radii exceed expectations from recent models by 14 ± 4% and 12 ± 4%, respectively. Following previous theories, we propose that this discrepancy is caused by the inhibition of convective energy transport by a strong internal magnetic field generated by dynamo effect in these two fast-rotating stars. A comparison with the almost identical twin Proxima, which is rotating slowly, strengthens this hypothesis because the radius of Proxima does not appear to be inflated compared to models.
影响因子：
6.5
作者：
Fuhrmeister;Lalitha;Poppenhaeger;Rudolf;Liefke;Reiners;Schmitt;J. H. M. M
通讯作者：
J. H. M. M
使用 PHOENIX ACES 模型从高分辨率光谱中获取基本 M 矮星参数：I 参数精度和基准恒星
DOI：
10.1051/0004-6361/201322261
发表时间：
2016
期刊：
arXiv: Solar and Stellar Astrophysics
影响因子：
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作者：
Passegger;Wende-von Berg;Reiners
通讯作者：
Reiners
影响因子：
6.5
作者：
Baraffe, Isabelle;Homeier, Derek;Chabrier, Gilles
通讯作者：
Chabrier, Gilles