Nodal Precession and Tidal Evolution of Two Hot Jupiters: WASP-33 b and KELT-9 b

Stephan, Alexander P.; Ji, Wang; Cauley, P. Wilson; Gaudi, B. Scott; Ilyin, I.; Johnson, Marshall C.; Strassmeier, K. G.

doi:10.3847/1538-4357/ac6b9a

Cited by 11 publications

(10 citation statements)

References 52 publications

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“…The best-fit eccentricity value agrees with a circular orbit only at 4 σ. Furthermore, Stephan et al (2022) recently found a nodal precession trend using radial velocity measurements, which could also have an effect on the transit timings, albeit generally a much smaller signal in comparison to apsidal precession for typical hot Jupiters. Transit duration variations are a better indicator for nodal precession (Miralda-Escudé 2002;Ragozzine & Wolf 2009;Damiani & Lanza 2011).…”

Section: Timing Analysismentioning

confidence: 99%

Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b

Jan-Vincent¹,

Smith²,

Barros³

et al. 2023

A&A

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Context. Tidal orbital decay is suspected to occur especially for hot Jupiters, with the only observationally confirmed case of this being WASP-12 b. By examining this effect, information on the properties of the host star can be obtained using the so-called stellar modified tidal quality factor Q * , which describes the efficiency with which kinetic energy of the planet is dissipated within the star. This can help to get information about the interior of the star. Aims. In this study, we aim to improve constraints on the tidal decay of the KELT-9, KELT-16 and WASP-4 systems, to find evidence for or against the presence of this particular effect. With this, we want to constrain each star's respective Q * value. In addition to that, we also aim to test the existence of the transit timing variations (TTVs) in the HD 97658 system, which previously favoured a quadratic trend with increasing orbital period. Methods. Making use of newly acquired photometric observations from CHEOPS (CHaracterising ExOplanet Satellite) and TESS (Transiting Exoplanet Survey Satellite), combined with archival transit and occultation data, we use Markov chain Monte Carlo (MCMC) algorithms to fit three models, a constant period model, an orbital decay model, and an apsidal precession model, to the data. Results. We find that the KELT-9 system is best described by an apsidal precession model for now, with an orbital decay trend at over 2 σ being a possible solution as well. A Keplerian orbit model with a constant orbital period fits the transit timings of KELT-16 b the best due to the scatter and scale of their error bars. The WASP-4 system is represented the best by an orbital decay model at a 5 σ significance, although apsidal precession cannot be ruled out with the present data. For HD 97658 b, using recently acquired transit observations, we find no conclusive evidence for a previously suspected strong quadratic trend in the data.

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Section: Timing Analysismentioning

confidence: 99%

Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b

Jan-Vincent¹,

Smith²,

Barros³

et al. 2023

A&A

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“…We consider this discrepancy more likely real, and possibly indicative of a pre-eclipse-post-eclipse asymmetry. We exclude that this is caused by the nodal precession of KELT-9b (Stephan et al 2022), which would only change the inclination of the orbit by about 1 • in three years and whose effect on K p would be at the 10 −4 level. We return to our interpretation of the variation of K p in the following section and in section 4.3.…”

Section: Confirmation Of Iron Emission Lines From the Dayside Of Kelt-9bmentioning

confidence: 99%

The GAPS Programme at TNG

Pino

Brogi

Désert

et al. 2022

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Aims. We present a novel method for studying the thermal emission of exoplanets as a function of orbital phase at very high spectral resolution, and use it to investigate the climate of the ultra-hot Jupiter KELT-9b. Methods. We combine three nights of HARPS-N and two nights of CARMENES optical spectra, covering orbital phases between quadratures (0.25 < ϕ < 0.75), when the planet shows its day-side hemisphere with different geometries. We co-add the signal of thousands of Fe i lines through cross-correlation, which we map to a likelihood function. We investigate the phase-dependence of two separate observable quantities, namely (i) the line depths of Fe i and (ii) their Doppler shifts, introducing a new method that exploits the very high spectral resolution of our observations. Results. We confirm a previous detection of Fe i emission, and demonstrate a precision of 0.5 km s −1 on the orbital properties of KELT-9b when combining all nights of observations. By studying the phase-resolved Doppler shift of Fe i lines, we detect an anomaly in the planet's orbital radial velocity well-fitted with a slightly eccentric orbital solution (e = 0.016 ± 0.003, ω = 150 +13 • −11 , 5σ preference). However, we argue that this anomaly is caused by atmospheric circulation patterns, and can be explained if neutral iron gas is advected by day-to-night atmospheric wind flows of the order of a few km s −1 . We additionally show that the Fe i emission line depths are symmetric around the substellar point within 10 • (2σ), possibly indicating the lack of a large hot-spot offset at the altitude probed by neutral iron emission lines. Finally, we do not obtain a significant preference for models with a strong phase-dependence of the Fe i emission line strength. We show that these results are qualitatively compatible with predictions from general circulation models (GCMs) for ultra-hot Jupiter planets. Conclusions. Very high-resolution spectroscopy phase curves are of sufficient sensitivity to reveal a phase dependence in both the line depths and their Doppler shifts throughout the orbit. They constitute an under-exploited treasure trove of information that is highly complementary to space-based phase curves obtained with HST and JWST, and open a new window onto the still poorly understood climate and atmospheric structure of the hottest planets known to date.

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“…We note here that given the high impact parameter for the transit of TOI-640 b, any change in orbital inclination caused by for example nodal precession (see e.g. Szabó et al 2012;Johnson et al 2015;Watanabe et al 2020Watanabe et al , 2022Stephan et al 2022) may be picked up by future photometric (TESS) observations.…”

Section: Refined Parameters For Toi-640 Bmentioning

confidence: 89%

A puffy polar planet

E.¹,

Albrecht²,

Gandolfi³

et al. 2023

A&A

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TOI-640 b is a hot, puffy Jupiter with a mass of 0.57 ± 0.02 MJ and radius of 1.72 ± 0.05 RJ, orbiting a slightly evolved F-type star with a separation of 6.33−0.06+0.07 R⋆. Through spectroscopic in-transit observations made with the HARPS spectrograph, we measured the Rossiter-McLaughlin effect, analysing both in-transit radial velocities and the distortion of the stellar spectral lines. From these observations, we find the host star to have a projected obliquity of λ = 184 ± 3°. From the TESS light curve, we measured the stellar rotation period, allowing us to determine the stellar inclination, i⋆ = 23−2+3°, meaning we are viewing the star pole-on. Combining this with the orbital inclination allowed us to calculate the host star obliquity, ψ = 104 ± 2°. TOI-640 b joins a group of planets orbiting over stellar poles within the range 80°–125°. The origin of this orbital configuration is not well understood.

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Nodal Precession and Tidal Evolution of Two Hot Jupiters: WASP-33 b and KELT-9 b

Cited by 11 publications

References 52 publications

Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b

Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b

The GAPS Programme at TNG

A puffy polar planet

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