Deciphering the atmosphere of HAT-P-12b: solving discrepant results

Alexoudi, X.; Mallonn, M.; Essen, C. von; Turner, Jake D.; Keles, Engin; Southworth, J.; Mancini, L.; Ciceri, S.; Granzer, T.; Denker, C.; Dineva, Ekaterina; Strassmeier, K. G.

doi:10.1051/0004-6361/201833691

Cited by 63 publications

(67 citation statements)

References 71 publications

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“…The shape of the transmission spectrum at visible wavelengths matches the results of previous analyses of the HST STIS data by Sing et al (2016) and Alexoudi et al (2018). It is worth mentioning that an earlier study of HAT-P-12b's atmosphere using ground-based broadband photometry produced a flat transmission spectrum throughout the visible wavelength range (Mallonn et al 2015), consistent with an opaque layer of clouds as opposed to Rayleigh scattering.…”

Section: Spectroscopic Light-curve Fitssupporting

confidence: 85%

“…In addition, none of the transit light curves analyzed in this work show evidence for occulted spots. It is notable that HAT-P-12b has an optical transmission spectrum that shows a slope indicative of Rayleigh scattering Alexoudi et al 2018 and this work), while the host star has low stellar activity. This is in contrast to the paradigmatic case of HD 189733b, which has a clear optical scattering slope and an active host star.…”

Section: Spitzer Iracmentioning

confidence: 55%

“…A previous analysis showed that the near-infrared transmission spectrum was flat, indicating the presence of high-altitude aerosols (Line et al 2013). This planet has also been observed in transit at visible wavelengths both from the ground (Mallonn et al 2015;Alexoudi et al 2018) and from space Alexoudi et al 2018), with the latter studies revealing a slope in the optical transmission spectrum indicative of Rayleigh scattering by fine aerosol particles in the upper atmosphere (Barstow et al 2017).…”

Section: Introductionmentioning

confidence: 89%

“…Observations of two transits were carried Table 1. This set of observations has been analyzed in two previous independent studies: Sing et al (2016) and Alexoudi et al (2018). The raw images are flat-fielded using the latest version of CALSTIS.…”

Section: Hst Stismentioning

confidence: 99%

“…It is worth mentioning that an earlier study of HAT-P-12b's atmosphere using ground-based broadband photometry produced a flat transmission spectrum throughout the visible wavelength range (Mallonn et al 2015), consistent with an opaque layer of clouds as opposed to Rayleigh scattering. This discrepancy was discussed in Alexoudi et al (2018) P-12b's orbit, which are correlated with transit depths and can yield wavelength-dependent shifts that alter the apparent transmission spectrum slope in the optical.…”

Section: Spectroscopic Light-curve Fitsmentioning

confidence: 99%

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Optical to Near-infrared Transmission Spectrum of the Warm Sub-Saturn HAT-P-12b

Wong

Benneke

Gao

et al. 2020

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We present the transmission spectrum of HAT-P-12b through a joint analysis of data obtained from the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) and Wide Field Camera 3 (WFC3) and Spitzer, covering the wavelength range 0.3-5.0 µm. We detect a muted water vapor absorption feature at 1.4 µm attenuated by clouds, as well as a Rayleigh scattering slope in the optical indicative of small particles. We interpret the transmission spectrum using both the state-ofthe-art atmospheric retrieval code SCARLET and the aerosol microphysics model CARMA. These models indicate that the atmosphere of HAT-P-12b is consistent with a broad range of metallicities between several tens to a few hundred times solar, a roughly solar C/O ratio, and moderately efficient vertical mixing. Cloud models that include condensate clouds do not readily generate the sub-micron particles necessary to reproduce the observed Rayleigh scattering slope, while models that incorporate photochemical hazes composed of soot or tholins are able to match the full transmission spectrum. From a complementary analysis of secondary eclipses by Spitzer, we obtain measured depths of 0.042% ± 0.013% and 0.045% ± 0.018% at 3.6 and 4.5 µm, respectively, which are consistent with a blackbody temperature of 890 +60 −70 K and indicate efficient day-night heat recirculation. HAT-P-12b joins the growing number of well-characterized warm planets that underscore the importance of clouds and hazes in our understanding of exoplanet atmospheres.

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Section: Spectroscopic Light-curve Fitssupporting

confidence: 85%

Section: Spitzer Iracmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 89%

Section: Hst Stismentioning

confidence: 99%

Section: Spectroscopic Light-curve Fitsmentioning

confidence: 99%

See 3 more Smart Citations

Optical to Near-infrared Transmission Spectrum of the Warm Sub-Saturn HAT-P-12b

Wong

Benneke

Gao

et al. 2020

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Comparative study of nearly‐grazing and fully‐grazing exoplanet system parameters derived with TESS and ground‐based instruments

et al. 2023

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Grazing transiting systems are rare and difficult to parameterize due to their partial transit geometry. We investigated a sample of 43 nearly‐grazing to fully‐grazing transiting exoplanetary systems, using datasets provided by the Transiting Exoplanet Satellite Survey (TESS), aiming first to refine major system parameters. We focus on the two parameters, impact parameter b$$ b $$ and planetary radius Rp$$ {R}_{\mathrm{p}} $$, through a comparison of TESS light curves with ground‐based light curves. We investigate if there is a potential systematic trend between ground‐based and space‐based investigations that would possibly lead to a redefinition of the grazing nature of those exoplanetary systems. Our results have shown that the b$$ b $$ value is confirmed for most of the systems within 2σ$$ 2\sigma $$, and refined significantly for Kilodegree Extremely Little Telescope (KELT)‐8 b, while the uncertainty on b$$ b $$ was improved for five systems with b>0.8$$ b>0.8 $$. The Rp$$ {R}_{\mathrm{p}} $$ measurements of four systems were successfully refined, while the uncertainty of Rp$$ {R}_{\mathrm{p}} $$ was improved for the majority of exoplanets with b>0.9$$ b>0.9 $$. Furthermore, a systematic trend is more pronounced for systems with b>0.9$$ b>0.9 $$, where there is a mean overestimation on the ground‐based derived Rp$$ {R}_{\mathrm{p}} $$ by 0.15RJ$$ 0.15{R}_{\mathrm{J}} $$. We concluded eventually that from our sample only five systems are truly grazing, while four systems that were considered as grazing are not.

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On the parameter refinement of inflated exoplanets with large radius uncertainty based on TESS observations

Alexoudi

2022

Astron Nachr

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We revisited 10 known exoplanetary systems using publicly available data provided by the transiting exoplanet survey satellite (TESS). The sample presented in this work consists of short period transiting exoplanets, with inflated radii and large reported uncertainty on their planetary radii. The precise determination of these values is crucial in order to develop accurate evolutionary models and understand the inflation mechanisms of these systems. Aiming to evaluate the planetary radius measurement, we made use of the planet-to-star radii ratio, a quantity that can be measured during a transit event. We fit the obtained transit light curves of each target with a detrending model and a transit model. Furthermore, we used emcee, which is based on a Markov chain Monte Carlo approach, to assess the best fit posterior distributions of each system parameter of interest. We refined the planetary radius of WASP-140 b by approximately 12%, and we derived a better precision on its reported asymmetric radius uncertainty by approximately 86 and 67%. We also refined the orbital parameters of WASP-120 b by 2𝜎. Moreover, using the high-cadence TESS datasets, we were able to solve a discrepancy in the literature, regarding the planetary radius of the exoplanet WASP-93 b. For all the other exoplanets in our sample, even though there is a tentative trend that planetary radii of (near-) grazing systems have been slightly overestimated in the literature, the planetary radius estimation and the orbital parameters were confirmed with independent observations from space, showing that TESS and ground-based observations are overall in good agreement.

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Deciphering the atmosphere of HAT-P-12b: solving discrepant results

Cited by 63 publications

References 71 publications

Optical to Near-infrared Transmission Spectrum of the Warm Sub-Saturn HAT-P-12b

Optical to Near-infrared Transmission Spectrum of the Warm Sub-Saturn HAT-P-12b

Comparative study of nearly‐grazing and fully‐grazing exoplanet system parameters derived with TESS and ground‐based instruments

On the parameter refinement of inflated exoplanets with large radius uncertainty based on TESS observations

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