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Doppler shifted transient sodium detection by KECK/HIRES

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Title: Doppler shifted transient sodium detection by KECK/HIRES
Authors: Unni, Athira, Oza, Apurva V., Hoeijmakers, H. Jens, Seidel, Julia V., Sivarani, Thirupathi, Schmidt, Carl A., Kesseli, Aurora Y., de Kleer, Katherine, Baker, Ashley D., Gebek, Andrea, Westram, Moritz Meyer zu, Fisher, Chloe, Sallum, Steph, Bestha, Manjunath, Bello-Arufe, Aaron
Contributors: Lund University, Faculty of Science, Department of Physics, Astrophysics, Lunds universitet, Naturvetenskapliga fakulteten, Fysiska institutionen, Astrofysik, Originator, Lund University, Profile areas and other strong research environments, Strategic research areas (SRA), eSSENCE: The e-Science Collaboration, Lunds universitet, Profilområden och andra starka forskningsmiljöer, Strategiska forskningsområden (SFO), eSSENCE: The e-Science Collaboration, Originator
Source: Monthly Notices of the Royal Astronomical Society: Letters. 540(1):L48-L53
Subject Terms: Natural Sciences, Physical Sciences, Astronomy, Astrophysics and Cosmology, Naturvetenskap, Fysik, Astronomi, astrofysik och kosmologi
Description: We carried out the first high-resolution transit observations of the exoplanet WASP-49 Ab with Keck/HIRES. Upon custom wavelength calibration we achieve a Doppler RV precision of < 60 m s−1. . This is an improvement in RV stability of roughly 240 m s−1 with respect to the instrument standard. We report an average sodium flux residual of (Formula presented) per cent t (8.0σ) comparable to previous studies. Interestingly, an average Doppler shift of −6.2 ± 0.5 km s−1 (12.4 σ) is identified offset from the exoplanet rest frame. The velocity residuals in time trace a blueshift (Formula presented) to redshift (Formula presented) suggesting the origin of the observed sodium is unlikely from the atmosphere of the planet. The average Na light curves indicate a depth of (Formula presented) per cent(11.7 σ) enduring ≲90 min with a half-max duration of $/sim$ 40.1 min. Frequent high-resolution spectroscopic observations will be able to characterize the periodicity of the observed Doppler shifts. Considering the origin of the transient sodium gas is of unknown geometry, a co-orbiting natural satellite may be a likely source.
Access URL: https://doi.org/10.1093/mnrasl/slaf031
Database: SwePub
Description
Abstract:We carried out the first high-resolution transit observations of the exoplanet WASP-49 Ab with Keck/HIRES. Upon custom wavelength calibration we achieve a Doppler RV precision of < 60 m s−1. . This is an improvement in RV stability of roughly 240 m s−1 with respect to the instrument standard. We report an average sodium flux residual of (Formula presented) per cent t (8.0σ) comparable to previous studies. Interestingly, an average Doppler shift of −6.2 ± 0.5 km s−1 (12.4 σ) is identified offset from the exoplanet rest frame. The velocity residuals in time trace a blueshift (Formula presented) to redshift (Formula presented) suggesting the origin of the observed sodium is unlikely from the atmosphere of the planet. The average Na light curves indicate a depth of (Formula presented) per cent(11.7 σ) enduring ≲90 min with a half-max duration of $/sim$ 40.1 min. Frequent high-resolution spectroscopic observations will be able to characterize the periodicity of the observed Doppler shifts. Considering the origin of the transient sodium gas is of unknown geometry, a co-orbiting natural satellite may be a likely source.
ISSN:17453933
DOI:10.1093/mnrasl/slaf031