论文标题

棕色矮人的大气模型被白矮人照射:热和超热木星的类似物

Atmosphere Models of Brown Dwarfs Irradiated by White Dwarfs: Analogues for Hot and Ultra-Hot Jupiters

论文作者

Lothringer, Joshua D., Casewell, Sarah L.

论文摘要

辐照的棕色矮人(BDS)提供了自然实验室,以测试我们对子宫和辐照气氛的理解。已经观察到围绕白色矮人(WDS)的少数短期BDS,但独特的强烈紫外线主导的辐射提出了建模挑战。在这里,我们介绍了第一个完全自洽的1D大气模型,该模型考虑了紫外线辐射对物体温度结构的影响。我们探索两个BD-WD系统,即WD-0137-349和Epic-212235321。 WD-0137-349B具有平衡温度,将其置于热和超热木星之间的过渡中,而Epic-212235321b的平衡温度高于除KELT-9B以外的所有超高固定器。我们探索了受辐照的BD大气的一些特殊方面,并表明现有的光度法可以很好地适合我们的模型。此外,可以通过强烈的辐照诱导的温度反演来解释这些BD的原子发射线的检测,这类似于最近在超热木星中探索的反转。我们的WD-0137-349B模型可以重现许多但不是所有这些原子线的观察到的等效宽度。我们使用这些对象的观察到的光度法使用凤凰外球星回收算法(PETRA)来检索温度结构,并证明结构与我们的模型一致,尽管在低压下略凉。然后,我们讨论了这类辐照的棕色矮人和低质量超热木星之间的相似性和差异。最后,我们描述了在颜色数级空间中受照射的BDS的行为,以表明使用原本经过测试的孤立对象的方法对受辐照的BD进行分类的困难。

Irradiated brown dwarfs (BDs) provide natural laboratories to test our understanding of substellar and irradiated atmospheres. A handful of short-period BDs around white dwarfs (WDs) have been observed, but the uniquely intense UV-dominated irradiation presents a modeling challenge. Here, we present the first fully self-consistent 1D atmosphere models that take into account the UV irradiation's effect on the object's temperature structure. We explore two BD-WD systems, namely WD-0137-349 and EPIC-212235321. WD-0137-349B has an equilibrium temperature that would place it in the transition between hot and ultra-hot Jupiters, while EPIC-212235321B has an equilibrium temperature higher than all ultra-hot Jupiters except KELT-9b. We explore some peculiar aspects of irradiated BD atmospheres and show that existing photometry can be well-fit with our models. Additionally, the detections of atomic emission lines from these BDs can be explained by a strong irradiation-induced temperature inversion, similar to inversions recently explored in ultra-hot Jupiters. Our models of WD-0137-349B can reproduce the observed equivalent width of many but not all of these atomic lines. We use the observed photometry of these objects to retrieve the temperature structure using the PHOENIX ExoplaneT Retrieval Algorithm (PETRA) and demonstrate that the structures are consistent with our models, albeit somewhat cooler at low pressures. We then discuss the similarities and differences between this class of irradiated brown dwarf and the lower-mass ultra-hot Jupiters. Lastly, we describe the behavior of irradiated BDs in color-magnitude space to show the difficulty in classifying irradiated BDs using otherwise well-tested methods for isolated objects.

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