Temperature inversions on hot super-Earths: the case of CN in nitrogen-rich atmospheres

Zilinskas, Mantas; Miguel, Yamila; Lyu, Yanli; Bax, Morris

doi:10.1093/mnras/staa3415

Cited by 17 publications

(22 citation statements)

References 35 publications

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“…The HST WFC3 transmission spectrum of the highly irradiated super-Earth 55 Cnc e shows evidence for hydrogen cyanide (HCN; Tsiaras et al 2016a). However, the exact nature of its atmosphere, and whether it exists, is still highly debated (Madhusudhan et al 2012;Dorn et al 2019;Jindal et al 2020;Modirrousta-Galian et al 2020a;Zhang et al 2021;Zilinskas et al 2021). 3.…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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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“…• The HST WFC3 transmission spectrum of the highly irradiated Super-Earth 55 Cnc e shows evidence for Hydrogen Cyanide (HCN) (Tsiaras et al 2016c). However, the exact nature of its atmosphere, and whether it exists, is still highly debated (Madhusudhan et al 2012;Dorn et al 2019;Modirrousta-Galian et al 2020a;Jindal et al 2020;Zilinskas et al 2021;Zhang et al 2021) • LHS 1140 b, a super-Earth orbiting in the habitable-zone of its star, potentially hosts an atmosphere containing water vapour but the low SNR, and narrow wavelength coverage, of the data means this detection is tentative .…”

Section: Introductionmentioning

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

Preprint

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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) onboard the Hubble Space Telescope. We used the publicly available Iraclis pipeline to extract the planetary transmission spectra from the five visits and produce a precise transmission spectrum. We analysed 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 envelope, 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.

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“…The noise at 4 -5 µm is an artefact of generated synthetic stellar spectra. Zilinskas et al 2020Zilinskas et al , 2021. Its high surface temperature makes it also likely to have a partially molten crust, which would result in a silicate-rich atmosphere.…”

Section: Observabilitymentioning

confidence: 99%

Observability of Evaporating Lava Worlds

Zilinskas,

van Buchem,

Miguel

et al. 2022

Preprint

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Lava worlds belong to a class of short orbital period planets reaching dayside temperatures high enough to melt their silicate crust. Theory predicts that the resulting lava oceans outgas their volatile components, attaining equilibrium with the overlying vapour. This creates a tenuous, silicate-rich atmosphere that may be confined to the permanent dayside of the planet. JWST will provide the much needed sensitivity and spectral coverage to characterise these worlds. In this paper, we assess the observability of characterisable spectral features by self-consistently modelling silicate atmospheres for all the currently confirmed targets having sufficient substellar temperatures (> 1500 K). To achieve this we use outgassed equilibrium chemistry and radiative transfer methods to compute temperature-pressure profiles, atmospheric chemical compositions and emission spectra. We explore varying melt compositions, free of highly-volatile elements, accounting for possible atmospheric evolution. Our models include a large number of neutral and ionic species, as well as all up-to-date opacities. The results indicate that SiO and SiO 2 infrared features are the best, unique identifiers of silicate atmospheres, detectable using MIRI instrument of JWST. Detection of these two species in emission would allow for strong constraints on atmospheric thermal structure and possibly the composition of the melt. We also propose that certain species, e.g., TiO, may be directly tied to different classes of melts, possibly revealing surface and interior dynamics. Currently, there are nearly a dozen confirmed lava planets ideal for characterisation of silicate atmospheres using JWST, with two of these already accepted for the initial General Observers program.

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Temperature inversions on hot super-Earths: the case of CN in nitrogen-rich atmospheres

Cited by 17 publications

References 35 publications

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

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

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

Observability of Evaporating Lava Worlds

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