Toward Direct Detection of Hot Jupiters with Precision Closure Phase: Calibration Studies and First Results from the CHARA Array
Toward Direct Detection of Hot Jupiters with Precision Closure Phase: Calibration Studies and First Results from the CHARA Array
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通过精确闭合阶段直接探测热木星：校准研究和 CHARA 阵列的初步结果
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发表时间：
2011
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Az
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作者：
Ming Zhao;J. Monnier;X. Che;E. Pedretti;N. Thureau;G. Schaefer;T. Brummelaar;A. Mérand;S. Ridgway;H. Mcalister;N. Turner;J. Sturmann;L. Sturmann;P. J. Goldfinger;C. Lab.;U. Michigan;Supa;U. S. Andrews;Scotland;UK.;The Chara Array;Georgia State University;E. Observatory;National Optical Astronomy Observatory;Noao;Tucson;Az
近几年来，直接探测到来自附近热彗星的热辐射极大地提高了我们对太阳系外行星的认识。由于热木星系统可以被视为高对比度双星的类似物，地基红外长基线干涉仪有可能解决它们，并检测它们的热辐射与精确的闭合相位-一种方法，是免疫的系统误差引起的地球大气。在这项工作中，我们提出了直接检测附近的热彗星使用CHARA干涉仪阵列配备MIRC仪器的闭合相的研究。我们进行了闭合相模拟，并进行了大量的观察，以获得最佳的候选人。实验结果表明，该方法是可行的，具有高度稳定和精确的闭合相位。然而，我们也发现观测中的系统误差比预期的要大得多，很可能是由不同波长的色散引起的。我们发现，使用更高的光谱分辨率模式（例如，R = 150）可显著降低系统性。通过将观测运行中的所有校准器结合在一起，我们能够粗略地重新校准较低的光谱分辨率数据，使我们能够获得H波段的恒星-行星对比度的上限。这些数据还使我们能够得到精确的恒星半径为1.625 ± 0.011 R <$。我们的最佳上限对应于在1.52 μm处具有90%置信水平的2.1 × 103：1的对比度，这表明我们开始有能力用干涉测量来约束热彗星的大气模型。随着CHARA/MIRC最近和即将到来的改进，探测具有闭合相的热中子源的发射的前景是有希望的。
Direct detection of thermal emission from nearby hot Jupiters has greatly advanced our knowledge of extrasolar planets in recent years. Since hot Jupiter systems can be regarded as analogs of high-contrast binaries, ground-based infrared long-baseline interferometers have the potential to resolve them and detect their thermal emission with precision closure phase—a method that is immune to the systematic errors induced by the Earth’s atmosphere. In this work, we present closure-phase studies toward direct detection of nearby hot Jupiters using the CHARA interferometer array outfitted with the MIRC instrument. We carry out closure-phase simulations and conduct a large number of observations for the best candidate υ And. Our experiments suggest that the method is feasible with highly stable and precise closure phases. However, we also find much larger systematic errors than expected in the observations, most likely caused by dispersion across different wavelengths. We find that using higher spectral resolution modes (e.g., R = 150) can significantly reduce the systematics. By combining all calibrators in an observing run together, we are able to roughly recalibrate the lower spectral resolution data, allowing us to obtain upper limits of the star-planet contrast ratios of υ And b across the H band. The data also allow us to get a refined stellar radius of 1.625 ± 0.011 R⊙. Our best upper limit corresponds to a contrast ratio of 2.1 × 103 : 1 with 90% confidence level at 1.52 μm, suggesting that we are starting to have the capability of constraining atmospheric models of hot Jupiters with interferometry. With recent and upcoming improvements of CHARA/MIRC, the prospect of detecting emission from hot Jupiters with closure phases is promising.