Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b

Hoeijmakers, H. J.; Ehrenreich, D.; Heng, Kevin; Kitzmann, Daniel; Grimm, Simon L.; Allart, R.; Deitrick, Russell; Wyttenbach, A.; Oreshenko, Maria; Pino, L.; Rimmer, Paul B.; Molinari, E.; Fabrizio, L. Di

doi:10.1038/s41586-018-0401-y

Cited by 256 publications

(320 citation statements)

References 28 publications

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“…We can search for these species by cross-correlating with a model transmission spectrum, which stacks the signal from all of the absorption lines. This approach has been used successfully in the optical regime (Nugroho et al 2017;Hoeijmakers et al 2018Hoeijmakers et al , 2019, as well as the near-infrared (Snellen et al 2010;Brogi et al 2012;Rodler et al 2013;Lockwood et al 2014;Birkby et al 2013;Piskorz et al 2016;Birkby et al 2017;Brogi et al 2018;Hawker et al 2018). We use the X-COR pipeline, which was previously used to detect CO, H 2 O, and HCN in the dayside atmospheres of hot Jupiters (Hawker et al 2018;Cabot et al 2019).…”

Section: Cross-correlationmentioning

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

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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Section: Cross-correlationmentioning

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

106

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“…Observations from the ground and space have yielded detections of various atoms, molecules, and ions (e.g. Deming et al 2013;Sedaghati et al 2017;Spake et al 2018;Hoeijmakers et al 2018). Sufficiently high-precision observations contain information on terminator temperature structures (Barstow et al 2013;Rocchetto et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Why Is it So Cold in Here? Explaining the Cold Temperatures Retrieved from Transmission Spectra of Exoplanet Atmospheres

Macdonald

Goyal

Lewis

2020

ApJL

124

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Transmission spectroscopy is a powerful technique widely used to probe exoplanet terminators. Atmospheric retrievals of transmission spectra are enabling comparative studies of exoplanet atmospheres. However, the atmospheric properties inferred by retrieval techniques display a significant anomaly: most retrieved temperatures are far colder than expected. In some cases, retrieved temperatures are ∼ 1000 K colder than T eq . Here, we provide an explanation for this conundrum. We demonstrate that erroneously cold temperatures result when 1D atmospheric models are applied to spectra of planets with differing morning-evening terminator compositions. Despite providing an acceptable fit, 1D retrieval techniques artificially tune atmospheric parameters away from terminator-averaged properties. Retrieved temperature profiles are hundreds of degrees cooler and have weaker temperature gradients than reality. Retrieved abundances are mostly biased by > 1σ and sometimes by > 3σ, with the most extreme biases for ultra-hot Jupiters. When morning-evening compositional differences manifest for prominent opacity sources, H 2 O abundances retrieved by 1D models can be biased by over an order of magnitude. Finally, we demonstrate that these biases provide an explanation for the cold retrieved temperatures reported for WASP-17b and WASP-12b. To overcome biases associated with 1D atmospheric models, there is an urgent need to develop multidimensional retrieval techniques.

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“…CaII-paper-acc Barris et al 2018) and WASP-12b (Jensen et al 2018). Some atomic/ionic metal lines are also detected in UHJs, for instance, Fossati et al (2010) detected Mg ii in WASP-12b using UV transmission spectroscopy with the Hubble Space Telescope and various metal elements (including Fe, Ti, Mg, and Na) have been discovered in KELT-9b (Hoeijmakers et al 2018;Cauley et al 2019;Hoeijmakers et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Ionized calcium in the atmospheres of two ultra-hot exoplanets WASP-33b and KELT-9b

Yan

Casasayas-Barris

Molaverdikhani

et al. 2019

A&A

125

132

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Ultra-hot Jupiters are emerging as a new class of exoplanets. Studying their chemical compositions and temperature structures will improve the understanding of their mass loss rate as well as their formation and evolution. We present the detection of ionized calcium in the two hottest giant exoplanets -KELT-9b and WASP-33b. By utilizing transit datasets from CARMENES and HARPS-N observations, we achieved high confidence level detections of Ca ii using the cross-correlation method. We further obtain the transmission spectra around the individual lines of the Ca ii H&K doublet and the near-infrared triplet, and measure their line profiles. The Ca ii H&K lines have an average line depth of 2.02 ± 0.17 % (effective radius of 1.56 R p ) for WASP-33b and an average line depth of 0.78 ± 0.04 % (effective radius of 1.47 R p ) for KELT-9b, which indicates that the absorptions are from very high upper atmosphere layers close to the planetary Roche lobes. The observed Ca ii lines are significantly deeper than the predicted values from the hydrostatic models. Such a discrepancy is probably a result of hydrodynamic outflow that transports a significant amount of Ca ii into the upper atmosphere. The prominent Ca ii detection with the lack of significant Ca i detection implies that calcium is mostly ionized in the upper atmospheres of the two planets.

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Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b

Cited by 256 publications

References 28 publications

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

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

Why Is it So Cold in Here? Explaining the Cold Temperatures Retrieved from Transmission Spectra of Exoplanet Atmospheres

Ionized calcium in the atmospheres of two ultra-hot exoplanets WASP-33b and KELT-9b

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