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arXiv 2406.08348astro-ph.EP
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用ESPRESSO观测超热木星WASP-178 b的大气成分

The atmospheric composition of the ultra-hot Jupiter WASP-178 b observed with ESPRESSO

Y. C. Damasceno, J. V. Seidel, B. Prinoth, A. Psaridi, E. Esparza-Borges, M. Stangret, N. C. Santos, M. R. Zapatero-Osorio, Y. Alibert, R. Allart, T. Azevedo Si… 展开作者

Y. C. Damasceno, J. V. Seidel, B. Prinoth, A. Psaridi, E. Esparza-Borges, M. Stangret, N. C. Santos, M. R. Zapatero-Osorio, Y. Alibert, R. Allart, T. Azevedo Silva, M. Cointepas, A. R. Costa Silva, E. Cristo, P. Di Marcantonio, D. Ehrenreich, J. I. González Hernández, E. Herrero-Cisneros, M. Lendl, J. Lillo-Box, C. J. A. P. Martins, G. Micela, E. Pallé, S. G. Sousa, M. Steiner, V. Vaulato, Y. Zhao, F. Pepe

备注：
18 pages, 24 figures, accepted for publication in A&A
发表信息：
A&A Volume 689, A54 (2024)
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AI总结：

本文利用ESPRESSO凌星光谱在超热木星WASP-178 b大气中探测到NaI、Hα、Hβ、FeI和FeII等成分，发现Hα和Hβ展宽暗示大气逃逸，并指出MgI和FeII主导大气比此前认为的SiO云前体物情形更可能。

摘要：

我们利用两次ESPRESSO凌星观测，通过窄带和互相关技术搜寻超热木星WASP-178 b的大气成分，重点关注NaI、Hα、Hβ、Hγ、MgI、FeI和FeII的探测。此外，我们还展示了用于获取更新且精确的恒星、行星和轨道参数的并行测光数据。我们报告了NaI（5.5和5.4 σ）、Hα（13 σ）、Hβ（7.1 σ）的谱线分辨探测结果，以及MgI（4.6 σ）的初步探测。在互相关分析中，我们确认了MgI的探测（7.8和5.8 σ），并分别在两个夜晚报告了FeI（12和10 σ）和FeII（11和8.4 σ）的探测。然而，由于两个夜晚之间的结果存在差异，且与窄带导出的性质不一致，MgI的探测仍属初步结果。我们探测中层至高层大气的分辨谱线均未显示相对于行星静止参考系的显著位移，但Hα和Hβ分别表现出39.6 ± 2.1 km/s和27.6 ± 4.6 km/s的谱线展宽，表明可能开始发生大气逃逸。WASP-178 b与类似的超热木星不同，其高层大气缺乏强动力学特征，但FeI（15.66 ± 0.58 km/s）和FeII（11.32 ± 0.52 km/s）的展宽可能表明中层大气中存在风。未来对宿主恒星活动引起的流量变化影响的研究可能会为该问题提供更多线索。此前的研究表明WASP-178 b大气中存在SiO云前体物，且缺乏MgI和FeII。然而，我们的结果表明，行星大气以MgI和FeII为主的情形更为可能。基于我们的结果，我们鼓励未来观测进一步阐明这些大气性质。

英文摘要：

We search for atmospheric constituents for the UHJ WASP-178 b with two ESPRESSO transits using the narrow-band and cross-correlation techniques, focusing on the detections of NaI, H$α$, H$β$, H$γ$, MgI, FeI and FeII. Additionally, we show parallel photometry used to obtain updated and precise stellar, planetary and orbital parameters. We report the resolved line detections of NaI (5.5 and 5.4 $σ$), H$α$ (13 $σ$), H$β$ (7.1 $σ$), and tentatively MgI (4.6 $σ$). In cross-correlation, we confirm the MgI detection (7.8 and 5.8 $σ$) and additionally report the detections of FeI (12 and 10 $σ$) and FeII (11 and 8.4 $σ$), on both nights separately. The detection of MgI remains tentative, however, due to the differing results between both nights, as well as compared with the narrow-band derived properties. None of our resolved spectral lines probing the mid- to upper atmosphere show significant shifts relative to the planetary rest frame, however H$α$ and H$β$ exhibit line broadenings of 39.6 $\pm$ 2.1 km/s and 27.6 $\pm$ 4.6 km/s, respectively, indicating the onset of possible escape. WASP-178 b differs from similar UHJ with its lack of strong atmospheric dynamics in the upper atmosphere, however the broadening seen for FeI (15.66 $\pm$ 0.58 km/s) and FeII (11.32 $\pm$ 0.52 km/s) could indicate the presence of winds in the mid-atmosphere. Future studies on the impact of the flux variability caused by the host star activity might shed more light on the subject. Previous work indicated the presence of SiO cloud-precursors in the atmosphere of WASP-178 b and a lack of MgI and FeII. However, our results suggest that a scenario where the planetary atmosphere is dominated by MgI and FeII is more likely. In light of our results, we encourage future observations to further elucidate these atmospheric properties.

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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