The centre-to-limb variations of solar Fraunhofer lines imprinted upon lunar eclipse spectra

Yan, F.; Fosbury, R. A. E.; Petr-Gotzens, M. G.; Zhao, Gang; Πάλλη, Ε.

doi:10.1051/0004-6361/201425220

Cited by 41 publications

(32 citation statements)

References 34 publications

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“…As noted by Yan et al (2015), the CLV-induced effect on the light curves derived from transit spectroscopy becomes more pronounced when narrow spectral bands are used for integration in strong spectral lines. Although the use of broader bands reduces the influence of the CLV, a number of studies have found the planetary atmospheric signal to be concentrated in the cores of the line.…”

Section: Resultsmentioning

confidence: 88%

The center-to-limb variation across the Fraunhofer lines of HD 189733

Czesla

Klocová

Khalafinejad

et al. 2015

A&A

115

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The center-to-limb variation (CLV) describes the brightness of the stellar disk as a function of the limb angle. Across strong absorption lines, the CLV can vary quite significantly. We obtained a densely sampled time series of high-resolution transit spectra of the active planet host star HD 189733 with UVES. Using the passing planetary disk of the hot Jupiter HD 189733 b as a probe, we study the CLV in the wings of the Ca  H and K and Na  D 1 and D 2 Fraunhofer lines, which are not strongly affected by activity-induced variability.In agreement with model predictions, our analysis shows that the wings of the studied Fraunhofer lines are limb brightened with respect to the (quasi-)continuum. The strength of the CLV-induced effect can be on the same order as signals found for hot Jupiter atmospheres. Therefore, a careful treatment of the wavelength dependence of the stellar CLV in strong absorption lines is highly relevant in the interpretation of planetary transit spectroscopy.

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Section: Resultsmentioning

confidence: 88%

The center-to-limb variation across the Fraunhofer lines of HD 189733

Czesla

Klocová

Khalafinejad

et al. 2015

A&A

115

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“…This distorts the average stellar spectrum, and produces a residual in the ratio of intransit and out-of-transit spectra (the distortion is called the Rossiter-McLauglin effect, only considering stellar rotation). The residual can create spurious features in the transmission spectrum and photometric lightcurves of individual lines (Louden & Wheatley 2015;Yan et al 2015Yan et al , 2017Casasayas-Barris et al 2018. In order to evaluate the influence of CLV and RM effects in the observed data, we model them simultaneously in a manner similar to Casasayas- Barris et al (2019).…”

Section: Center-to-limb Variation and Rossiter-mclaughlin Effectsmentioning

confidence: 99%

Detection of neutral atomic species in the ultra-hot Jupiter WASP-121b

Cabot

Madhusudhan

Welbanks

et al. 2020

Monthly Notices of the Royal Astronomical Society

100

106

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The class of ultra-hot Jupiters comprises giant exoplanets undergoing intense irradiation from their host stars. They have proved to be a particularly interesting population for their orbital and atmospheric properties. One such planet, WASP-121 b, is in a highly misaligned orbit close to its Roche limit, and its atmosphere exhibits a thermal inversion. These properties make WASP-121 b an interesting target for additional atmospheric characterization. In this paper, we present analysis of archival high-resolution optical spectra obtained during transits of WASP-121 b. Artifacts from the Rossiter-McLaughlin effect and Center-to-Limb Variation are deemed negligible. However, we discuss scenarios where these effects warrant more careful treatment by modeling the WASP-121 system and varying its properties. We report a new detection of atmospheric absorption from Hα in the planet with a transit depth of 1.87 ± 0.11%. We further confirm a previous detection of the Na I doublet, and report a new detection of Fe I via cross-correlation with a model template. We attribute the Hα absorption to an extended Hydrogen atmosphere, potentially undergoing escape, and the Fe I to equilibrium chemistry at the planetary photosphere. These detections help to constrain the composition and chemical processes in the atmosphere of WASP-121 b.

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“…The stellar line profile varies during the transit due to the Rossiter-McLaughlin (RM) effect (Queloz et al 2000) and the centre-to-limb variation (CLV) effect (Yan et al 2015a;Czesla et al 2015;Yan et al 2017). We modelled the RM and CLV effects simultaneously following the method described in Yan & Henning (2018).…”

Section: Model Of Stellar Rm and CLV Effectsmentioning

confidence: 99%

Detection of the hydrogen Balmer lines in the ultra-hot Jupiter WASP-33b

Yan

Wyttenbach

Casasayas-Barris

et al. 2020

A&A

Self Cite

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Ultra-hot Jupiters (UHJs) are highly irradiated giant exoplanets with extremely high day-side temperatures, which lead to thermal dissociation of most of the molecular species. It is expected that the neutral hydrogen atom is one of the main species in the upper atmospheres of ultra-hot Jupiters. Neutral hydrogen has been detected in several UHJs by observing its Balmer line absorption. Here, we report four transit observations of the ultra-hot Jupiter WASP-33b, performed with the CARMENES and HARPS-North spectrographs, and the detection of the Hα, Hβ, and Hγ lines in the planetary transmission spectrum. The combined Hα transmission spectrum of the four transits has an absorption depth of 0.99±0.05 %, which corresponds to an effective radius of 1.31±0.01 R p. The strong Hα absorption indicates that the line probes the high-altitude thermosphere. We further fitted the three Balmer lines using the PAWN model, assuming that the atmosphere is hydrodynamic and in LTE. We retrieved a thermosphere temperature 12200 +1300 −1000 K and a mass-loss rateṀ = 10 11.8 +0.6 −0.5 g s −1. The retrieved large mass-loss rate is compatible with the "Balmer-driven" atmospheric escape scenario, in which the stellar Balmer continua radiation in the near-ultraviolet is substantially absorbed by the excited hydrogen atoms in the planetary thermosphere.

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The centre-to-limb variations of solar Fraunhofer lines imprinted upon lunar eclipse spectra

Cited by 41 publications

References 34 publications

The center-to-limb variation across the Fraunhofer lines of HD 189733

The center-to-limb variation across the Fraunhofer lines of HD 189733

Detection of neutral atomic species in the ultra-hot Jupiter WASP-121b

Detection of the hydrogen Balmer lines in the ultra-hot Jupiter WASP-33b

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