The GTC exoplanet transit spectroscopy survey

Murgas, F.; Chen, G.; Nortmann, L.; Πάλλη, Ε.; Nowak, G.

doi:10.1051/0004-6361/202038161

Cited by 30 publications

(58 citation statements)

References 66 publications

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“…Our results (Table 2) agree well with results from previous analyses (Section 4.1.1), and in particular with the results of Murgas et al (2020) who used the same datasets. Our retrieved planetary radius, temperature, and Rayleigh parameters are consistent with theirs.…”

Section: Retrieval Resultssupporting

confidence: 91%

Probing the atmosphere of WASP-69 b with low- and high-resolution transmission spectroscopy

Khalafinejad,

Molaverdikhani,

Blecic

et al. 2021

Preprint

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Consideration of both low-and high-resolution transmission spectroscopy is key for obtaining a comprehensive picture of exoplanet atmospheres. In studies of transmission spectra, the continuum information is well established with low-resolution spectra, while the shapes of individual lines are best constrained with high-resolution observations. In this work, we aim to merge high-with lowresolution transmission spectroscopy to place tighter constraints on physical parameters of the atmospheres. We present the analysis of three primary transits of WASP-69 b in the visible (VIS) channel of the CARMENES instrument and perform a combined lowand high-resolution analysis using additional data from HARPS-N, OSIRIS/GTC, and WFC3/HST already available in the literature. We investigate the Na i D 1 and D 2 doublet, Hα, the Ca ii infra-red triplet (IRT), and K i λ7699 Å lines, and we monitor the stellar photometric variability by performing long-term photometric observations with the STELLA telescope. During the first CARMENES observing night, we detected the planet Na i D 2 and D 1 lines at ∼ 7σ and ∼ 3σ significance levels, respectively. We measured a D 2 /D 1 intensity ratio of 2.5±0.7, which is in agreement with previous HARPS-N observations. Our modelling of WFC3 and OSIRIS data suggests strong Rayleigh scattering, solar to super-solar water abundance, and a highly muted Na feature in the atmosphere of this planet, in agreement with previous investigations of this target. We use the continuum information retrieved from the low-resolution spectroscopy as a prior to break the degeneracy between the Na abundance, reference pressure, and thermosphere temperature for the high-resolution spectroscopic analysis. We fit the Na i D 1 and D 2 lines individually and find that the posterior distributions of the model parameters agree with each other within 1σ. Our results suggest that local thermodynamic equilibrium processes can explain the observed D 2 /D 1 ratio because the presence of haze opacity mutes the absorption features.

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Section: Retrieval Resultssupporting

confidence: 91%

Probing the atmosphere of WASP-69 b with low- and high-resolution transmission spectroscopy

Khalafinejad,

Molaverdikhani,

Blecic

et al. 2021

Preprint

Self Cite

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“…Offsets between instruments can be caused for a number of reasons: due to imperfect correction of instrument systematics; from the use of different orbital parameters or limb-darkening coefficients during the light-curve fitting; or from stellar variability or activity (e.g., Stevenson et al 2014aStevenson et al , 2014bAlexoudi et al 2018;Tsiaras et al 2018;Yip et al 2020b;Bruno et al 2020;Murgas et al 2020;Pluriel et al 2020;Yip et al 2020a). Here, we fitted the data sets with the same limbdarkening laws and orbital parameters, ruling out that potential explanation.…”

Section: Retrieval Results and Atmospheric Temperaturementioning

confidence: 99%

WASP-117 b: An Eccentric Hot Saturn as a Future Complex Chemistry Laboratory

Anisman

Edwards

Changeat

et al. 2020

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We present spectral analysis of the transiting Saturn-mass planet WASP-117 b, observed with the G141 grism of the Hubble Space Telescopeʼs (HST) Wide Field Camera 3. We reduce and fit the extracted spectrum from the raw transmission data using the open-source software Iraclis before performing a fully Bayesian retrieval using the publicly available analysis suite TauREx 3.0. We detect water vapor alongside a layer of fully opaque cloud, retrieving a terminator temperature of =-+ T 833 term 156 260 K. In order to quantify the statistical significance of this detection, we employ the atmospheric detectability index (ADI), deriving a value of ADI=2.30, which provides positive but not strong evidence against the flat-line model. Due to the eccentric orbit of WASP-117 b, it is likely that chemical and mixing timescales oscillate throughout orbit due to the changing temperature, possibly allowing warmer chemistry to remain visible as the planet begins transit, despite the proximity of its point of ingress to apastron. We present simulated spectra of the planet as would be observed by the future space missions such as the Atmospheric Remote-sensing Infrared Exoplanet Large-survey and the James Webb Space Telescope and show that, despite not being able to probe such chemistry with current HST data, these observatories should make it possible in the not too distant future.

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“…While it has become common to combine data from different instruments, there may be an offset between the data sets. These offsets can occur owing to imperfect correction of instrument systematics, from the use of different orbital parameters or limbdarkening coefficients during the light-curve fitting, or from stellar variability or activity (e.g., Stevenson et al 2014aStevenson et al , 2014bMorello et al 2017;Tsiaras et al 2018;Bruno et al 2020;Yip et al 2020Yip et al , 2021Changeat et al 2020;Murgas et al 2020;Pluriel et al 2020;Schlawin et al 2021). As there is no wavelength overlap between our HST observations and the Note.…”

Section: Comparison With Previous Workmentioning

confidence: 99%

ARES.* V. No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b

Mugnai

Modirrousta-Galian

Edwards

et al. 2021

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We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm (∼500 K) super-Earth (1.13 R ⊕ ) that was obtained with the G141 grism (1.125-1.650 μm) of the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. We used the publicly available Iraclis pipeline to extract the planetary transmission spectra from the five visits and produced a precise transmission spectrum. We analyzed the spectrum using the TauREx3 atmospheric retrieval code, with which we show that the measurements do not contain molecular signatures in the investigated wavelength range and are best fit with a flat-line model. Our results suggest that the planet does not have a clear primordial, hydrogen-dominated atmosphere. Instead, GJ 1132 b could have a cloudy hydrogen-dominated atmosphere, have a very enriched secondary atmosphere, be airless, or have a tenuous atmosphere that has not been detected. Due to the narrow wavelength coverage of WFC3, these scenarios cannot be distinguished yet, but the James Webb Space Telescope may be capable of detecting atmospheric features, although several observations may be required to provide useful constraints.Unified Astronomy Thesaurus concepts: Exoplanet atmospheres (487); Astronomy data analysis (1858); Hubble Space Telescope (761); Exoplanets (498)

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The GTC exoplanet transit spectroscopy survey

Cited by 30 publications

References 66 publications

Probing the atmosphere of WASP-69 b with low- and high-resolution transmission spectroscopy

Probing the atmosphere of WASP-69 b with low- and high-resolution transmission spectroscopy

WASP-117 b: An Eccentric Hot Saturn as a Future Complex Chemistry Laboratory

ARES.* V. No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b

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