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标题：The GAPS Programme with HARPS-N at TNG
其他标题：XIX. Atmospheric Rossiter-McLaughlin effect and improved parameters of KELT-9b★★★
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作者：F. Borsa ; M. Rainer ; A. S. Bonomo 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：631
页码：1-8
DOI：10.1051/0004-6361/201935718
语种：English
出版社：EDP Sciences
摘要：Aims.In the framework of the GAPS project, we observed the planet-hosting star KELT-9 (A-type star,vsini~ 110 km s−1) with the HARPS-N spectrograph at the Telescopio NazionaleGalileo. In this work we analyse the spectra and the extracted radial velocities to constrain the physical parameters of the system and to detect the planetary atmosphere of KELT-9b.Methods.We extracted the mean stellar line profiles from the high-resolution optical spectra via an analysis based on the least-squares deconvolution technique. Then we computed the stellar radial velocities with a method optimised for fast rotators by fitting the mean stellar line profile with a purely rotational profile instead of using a Gaussian function.Results.The new spectra and analysis led us to update the orbital and physical parameters of the system, improving in particular the value of the planetary mass toMp= 2.88 ± 0.35MJup. We discovered an anomalous in-transit radial velocity deviation from the theoretical Rossiter-McLaughlin effect solution, calculated from the projected spin-orbit angleλ= −85.78 ± 0.46 degrees measured with Doppler tomography. We prove that this deviation is caused by the planetary atmosphere of KELT-9b, thus we call this effect Atmospheric Rossiter-McLaughlin effect. By analysing the magnitude of the radial velocity anomaly, we obtained information on the extension of the planetary atmosphere as weighted by the model used to retrieve the stellar mean line profiles, which is up to 1.22 ± 0.02Rp.Conclusions.The Atmospheric Rossiter-McLaughlin effect will be observable for other exoplanets whose atmosphere has non-negligible correlation with the stellar mask used to retrieve the radial velocities, in particular ultra-hot Jupiters with iron in their atmospheres. The duration and amplitude of the effect will depend not only on the extension of the atmosphere, but also on the in-transit planetary radial velocities and on the projected rotational velocity of the parent star.
关键词：Key wordsenplanetary systemstechniques: spectroscopictechniques: radial velocitiesplanets and satellites: atmospheresstars: individual: KELT-9