A data-driven approach to constraining the atmospheric temperature structure of the ultra-hot Jupiter KELT-9b

Fossati, L.; Shulyak, D.; Sreejith, A. G.; Koskinen, Tommi; Young, Mitchell E.; Cubillos, Patricio; Lara, L. M.; Rengel, Miriam; Cauley, P. Wilson; Turner, Jake D.; Wyttenbach, A.; Yan, F.

doi:10.1051/0004-6361/202039061

Cited by 32 publications

(53 citation statements)

References 85 publications

(209 reference statements)

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“…The pretabulated cross 1 http://kurucz.harvard.edu/linelists/gfall/ sections of these molecules were taken from the public opacity database for exoplanetary atmospheres 2 . We also extended continuum opacity sources by including, for example, continuum transitions of H − , He − , and metals (see Fossati et al 2020Fossati et al , 2021. The HELIOS calculations were performed assuming local thermodynamic equilibrium.…”

Section: Comparison With Self-consistent Modelsmentioning

confidence: 99%

“…Ultra-hot Jupiters (UHJs) are giant exoplanets with very high dayside temperatures that typically exceed 2000 K. Theoreti-cal studies suggest that their properties are different from those of planets with more modest temperatures. For example, their dayside atmospheres can be dominated by atoms and ions with a large number of molecules that are thermally dissociated (e.g., Lothringer et al 2018;Parmentier et al 2018;Kitzmann et al 2018;Fossati et al 2020). These planets have ex-treme differences in their dayside to nightside temperature and are also different chemically (e.g., Bell & Cowan 2018;Komacek & Tan 2018;Tan & Komacek 2019;Helling et al 2019;Molaverdikhani et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b

Yan,

Reiners,

Pallé

et al. 2022

Preprint

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Ultra-hot Jupiters (UHJs) are gas giants with very high equilibrium temperatures. In recent years, multiple chemical species, including various atoms and ions, have been discovered in their atmospheres. Most of these observations have been performed with transmission spectroscopy, although UHJs are also ideal targets for emission spectroscopy due to their strong thermal radiation. We present highresolution thermal emission spectroscopy of the transiting UHJ KELT-20b/MASCARA-2b. The observation was performed with the CARMENES spectrograph at orbital phases before and after the secondary eclipse. We detected atomic Fe using the cross-correlation technique. The detected Fe lines are in emission, which unambiguously indicates a temperature inversion on the dayside hemisphere. We furthermore retrieved the temperature structure with the detected Fe lines. The result shows that the atmosphere has a strong temperature inversion with a temperature of 4900 ± 700 K and a pressure of 10 −4.8 +1.0 −1.1 bar at the upper layer of the inversion. A joint retrieval of the CARMENES data and the TESS secondary eclipse data returns a temperature of 2550 +150 −250 K and a pressure of 10 −1.5 +0.7 −0.6 bar at the lower layer of the temperature inversion. The detection of such a strong temperature inversion is consistent with theoretical simulations that predict an inversion layer on the dayside of UHJs. The joint retrieval of the CARMENES and TESS data demonstrates the power of combing high-resolution emission spectroscopy with secondary eclipse photometry in characterizing atmospheric temperature structures.

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Section: Comparison With Self-consistent Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b

Yan,

Reiners,

Pallé

et al. 2022

Preprint

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“…Wyttenbach et al 2020). Fossati et al (2020) discuss the differences in the Hα and Hβ lines as observed by different groups with different instruments and different reduction pipelines. Employing non-LTE radiative transfer, a temperature of 10 4 .…”

Section: Introductionmentioning

confidence: 98%

Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)

Helling

Lewis

Samra

et al. 2021

A&A

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Context. Ultra-hot Jupiters are the hottest exoplanets that have been discovered so far. Observations begin to provide insight into the composition of their extended atmospheres and their chemical day/night asymmetries. Both are strongly affected by cloud formation. Aims. We explore trends in cloud properties for a sample of five giant gas planets: the hot gas giant WASP-43b and the four ultra-hot Jupiters (UHJs) WASP-18b, HAT-P-7b, WASP-103b, and WASP-121b. This provides a reference frame for cloud properties for the JWST targets WASP-43b and WASP-121b. We further explore chemically inert tracers to observe geometrical asymmetries of UHJs and if the location of the inner boundary of a 3D global circulation model (3D GCM) matters for the clouds that form. Methods. A homogeneous set of 3D GCM results was used as input for a kinetic cloud formation code to evaluate the cloud opacity and gas parameters such as C/O, mean molecular weight, and degree of ionisation. We cast our results in terms of integrated quantities to enable a global comparison between the sample planets. Results. The large day/night temperature differences of UHJs cause the following chemical asymmetries: cloud-free days but cloudy nights, atomic versus molecular gases and their different mean molecular weights, deep thermal ionospheres versus low-ionised atmospheres, and undepleted versus enhanced C/O. WASP-18b, as the heaviest planet in the sample, has the lowest global C/O. Conclusions. The global climate may be considered as similar amongst UHJs, but different to that of hot gas giants. The local weather, however, is individual for each planet since the local thermodynamic conditions, and hence the local cloud and gas properties, differ. The morning and the evening terminator of UHJs will carry signatures of their strong chemical asymmetry such that ingress and egress asymmetries can be expected. An increased C/O ratio is a clear sign of cloud formation, making cloud modelling a necessity when utilising C/O (or other mineral ratios) as a tracer for planet formation. The changing geometrical extension of the atmosphere from the day to the nightside may be probed through chemically inert species such as helium. Ultra-hot Jupiters are likely to develop deep atmospheric ionospheres which may impact the atmosphere dynamics through magneto-hydrodynamic processes.

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“…It is subject to intense irradiation from the star and extreme atmospheric escape due to its large extended hydrogen envelope reaching the Roche-Lobe limit (Yan & Henning 2018;Wyttenbach et al 2020). Measurements of the neutral iron line by Pino et al (2020) imply the presence of a thermal inversion, as does modeling by Fossati et al (2020).…”

Section: Introductionmentioning

confidence: 99%

The Hubble WFC3 Emission Spectrum of the Extremely Hot Jupiter KELT-9b

Changeat

Edwards

2021

ApJL

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Recent studies of ultra-hot Jupiters suggested that their atmospheres could have thermal inversions due to the presence of optical absorbers such as titanium oxide (TiO), vanadium oxide (VO), iron hydride (FeH), and other metal hydride/oxides. However, it is expected that these molecules would thermally dissociate at extremely high temperatures, thus leading to featureless spectra in the infrared. KELT-9 b, the hottest exoplanet discovered so far, is thought to belong to this regime and host an atmosphere dominated by neutral hydrogen from dissociation and atomic/ionic species. Here, we analyzed the eclipse spectrum obtained using the Hubble Space Telescope's Wide Field Camera 3 and, by utilizing the atmospheric retrieval code TauREx3, found that the spectrum is consistent with the presence of molecular species and is poorly fitted by a simple blackbody. In particular, we find that a combination of TiO, VO, FeH, and Hprovides the best fit when considering Hubble Space Telescope (HST), Spitzer, and TESS data sets together. Aware of potential biases when combining instruments, we also analyzed the HST spectrum alone and found that TiO and VO only were needed in this case. These findings paint a more complex picture of the atmospheres of ultra-hot planets than previously thought.Unified Astronomy Thesaurus concepts: Exoplanet atmospheres (487); Bayesian statistics (1900); Hot Jupiters (753); Chemical abundances (224)

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A data-driven approach to constraining the atmospheric temperature structure of the ultra-hot Jupiter KELT-9b

Cited by 32 publications

References 85 publications

Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b

Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b

Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)

The Hubble WFC3 Emission Spectrum of the Extremely Hot Jupiter KELT-9b

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