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arXiv 1805.04067astro-ph.EP
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用热模型重新评估系外行星的光变曲线

Reassessing Exoplanet Light Curves with a Thermal Model

Arthur D. Adams, Gregory Laughlin

摘要:

我们提出了一个统一的评估现有的近红外斯皮策太空望远镜观测的行星轴承恒星。使用一个简单的四参数黑体热模型,我们分析恒星的光度至少有一个斯皮策的IRAC波段已经获得了整个或一个显着的部分行星轨道。这类系统包括10个在圆形或近圆形轨道上具有热超导体的经过充分研究的系统(HAT-P-7、HD 149026、HD 189733、HD 209458、WASP-12、WASP-14、WASP-18、WASP-19、WASP-33和WASP-43),以及三颗在显着偏心轨道上拥有行星的恒星(GJ 436、HAT-P-2和HD 80606)。我们发现,我们的简单模型,在几乎所有的情况下,准确地再现了最小和最大的行星排放,以及这些极值相对于过境/二次日食的相位偏移。对于一个值得注意的例外,WASP-12 b,增加一个额外的参数来解释其潮汐畸变不足以重现其光度特征。全轨道测光可用于10颗行星的多个波长。我们发现,返回的参数值独立适合每个波段在很大程度上是一致的。然而,夜间温度的差异表明不同的大气层,每个层都有自己的特征最低温度。此外,不同类型的日冕表明光球的不透明度不同。虽然以前的工作已经指出了基于系统属性的光度特征的趋势,但我们不能最终确定物理模型参数的类似趋势。为了使全相位数据和物理模型之间的联系更加可靠,必须通过提高分辨率和仔细处理仪器系统学来获得更高的信噪比。

英文摘要:

We present a uniform assessment of existing near-infrared Spitzer Space Telescope observations of planet-bearing stars. Using a simple four-parameter blackbody thermal model, we analyze stars for which photometry in at least one of Spitzer's IRAC bands has been obtained over either the entirety or a significant fraction of the planetary orbit. Systems in this category comprise ten well-studied systems with Hot Jupiters on circular or near-circular orbits (HAT-P-7, HD 149026, HD 189733, HD 209458, WASP-12, WASP-14, WASP-18, WASP-19, WASP-33, and WASP-43), as well as three stars harboring planets on significantly eccentric orbits (GJ 436, HAT-P-2, and HD 80606). We find that our simple model, in almost all cases, accurately reproduces the minimum and maximum planetary emission, as well as the phase offsets of these extrema with respect to transits/secondary eclipses. For one notable exception, WASP-12 b, adding an additional parameter to account for its tidal distortion is not sufficient to reproduce its photometric features. Full-orbit photometry is available in multiple wavelengths for 10 planets. We find that the returned parameter values for independent fits to each band are largely in agreement. However, disagreements in night-side temperature suggest distinct atmospheric layers, each with their own characteristic minimum temperature. In addition, a diversity in albedos suggests variation in opacity of the photospheres. While previous works have pointed out trends in photometric features based on system properties, we cannot conclusively identify analogous trends for physical model parameters. To make the connection between full-phase data and physical models more robust, a higher signal-to-noise must come from both increased resolution and a careful treatment of instrumental systematics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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