Inferring heat recirculation and albedo for exoplanetary atmospheres: Comparing optical phase curves and secondary eclipse data

Paris, Philip von; Gratier, P.; Bordé, P.; Selsis, F.

doi:10.1051/0004-6361/201526297

Cited by 20 publications

(21 citation statements)

References 82 publications

(287 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No clear signs of clouds have been found, although for HAT-P-7b, results seem to indicate a small but not statistically very significant asymmetry consistent with previous phase curve analyses by von Paris et al (2016). There are several reasons for this.…”

Section: Discussionsupporting

confidence: 81%

“…This would suggest that the trailing limb appears slightly larger (of the order of a couple of scale heights). Such a result is actually consistent with the analysis of von Paris et al (2016) who found that the asymmetric phase curve of HAT-P-7b is more likely due to an asymmetry in scattering properties than due to a thermal offset, contrary to previous studies (e.g., Esteves et al 2015). However, given that the constraints are very weak, such a conclusion appears to be only tentative.…”

Section: Planetsupporting

confidence: 89%

“…We apply the new technique to two planets in the Kepler field with well-characterized asymmetric phase curves, namely Kepler-7b (e.g., Latham et al 2010;Demory et al 2011Demory et al , 2013Esteves et al 2015) and HAT-P-7b (Pál et al 2008;Borucki et al 2009;Welsh et al 2010;Esteves et al 2015;von Paris et al 2016). Furthermore, we analyze transit light curves of HD 209458b taken from Brown et al (2001;their Fig. 3) obtained from four transits observed with the Hubble Space Telescope.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Inferring asymmetric limb cloudiness on exoplanets from transit light curves

Paris

Gratier

Bordé

et al. 2016

A&A

Self Cite

View full text Add to dashboard Cite

Context. Clouds have been shown to be present in many exoplanetary atmospheres. Cloud formation modeling predicts considerable inhomogeneities of cloud cover, consistent with optical phase curve observations. However, optical phase curves cannot resolve some existing degeneracies between cloud location and cloud optical properties. Aims. We present a conceptually simple technique for detecting inhomogeneous cloud cover on exoplanets. Such an inhomogeneous cloud cover produces an asymmetric primary transit of the planet in front of the host star. Asymmetric transits produce characteristic residuals that are different from standard symmetric models. Furthermore, bisector spans can be used to determine asymmetries in the transit light curve. Methods. We apply a model of asymmetric transits to the light curves of HAT-P-7b, Kepler-7b, and HD 209458b and search for possible cloud signatures. The nearly uninterrupted Kepler photometry is particularly well suited for this method since it allows for a very high time resolution. Results. We do not find any statistically sound cloud signature in the data of the considered planets. For HAT-P-7b, a tentative detection of an asymmetric cloud cover is found, consistent with analysis of the optical phase curve. Based on Bayesian probability arguments, a symmetric model with an offset in the transit ephemeris is still the most viable model. This work demonstrates that for suitable targets, namely low-gravity planets around bright stars, the method can be used to constrain cloud cover characteristics and is thus a helpful additional tool for the study of exoplanetary atmospheres.

show abstract

Section: Discussionsupporting

confidence: 81%

Section: Planetsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Inferring asymmetric limb cloudiness on exoplanets from transit light curves

Paris

Gratier

Bordé

et al. 2016

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…These reflected light signatures complement the thermal structure and orbital information inferred from phase variations and secondary eclipses detected in the infrared (Harrington et al 2006;Knutson et al 2007;Kane & Gelino 2011a;Demory et al 2016). Secondary eclipse observations enable the measurement of atmospheric temperatures that are critical in modeling exoplanet atmospheres and interiors (Line & Yung 2013;von Paris et al 2016;Fortney et al 2019). Furthermore, the additional phase variation components of ellipsoidal variations and Doppler beaming can be used to distinguish between stellar and planetary companions to the host star (Drake 2003;Kane & Gelino 2012a).…”

Section: Phase Variations and Secondary Eclipsesmentioning

confidence: 77%

Science Extraction from TESS Observations of Known Exoplanet Hosts

Kane

Bean

Campante

et al. 2020

PASP

View full text Add to dashboard Cite

Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

show abstract

“…Both the optical and IR phase curves of HAT-P-7 b have been studied previously 5,6,9,[11][12][13] . The optical phase curve exhibits a significant fraction of thermal emission (potentially as high as 77% 6 ), due to the high temperature of the planet.…”

Section: Main Textmentioning

confidence: 99%

Variability in the atmosphere of the hot giant planet HAT-P-7 b

et al. 2016

View full text Add to dashboard Cite

As an exoplanet orbits its host star it reflects and emits light, forming a distinctive phase curve 1,2 . By observing this light, we can study the atmosphere and surface of distant planets. The planets in our Solar System show a wide range of atmospheric phenomena, with stable wind patterns, changing storms, and evolving anomalies. Brown dwarfs also exhibit atmospheric variability 3,4 . Such temporal variability in the atmosphere of a giant exoplanet has not to date been observed. HAT-P-7 b is an exoplanet with a known offset in the peak of its phase curve 5,6 . Here we present variations in the peak offset ranging between -0.086 +0.033 -0.033 to 0.143 +0.040 -0.037 in phase, implying that the peak brightness repeatedly shifts from one side of the planet's substellar point to the other. The variability occurs on a timescale of tens to hundreds of days. These shifts in brightness are indicative of variability in the planet's atmosphere, and result from a changing balance of thermal emission and reflected flux from the planet's dayside. We suggest that variation in wind speed in the planetary atmosphere, leading to variable cloud coverage on the dayside and a changing energy balance, is capable of explaining the observed variation. Time (BJD-2454833)Peak Offset (Phase) Author ContributionsDJA obtained and detrended the data, developed and fit the phase curve models, implemented the atmospheric model, produced the figures and wrote the manuscript. EdM developed the discussion, contributed to the tests performed to check the results, and tested the results with his own models. HPO contributed to the phase curve model, and produced visual interpretations of the results. JBa developed the discussion of the atmospheric processes behind the peak offset variations. JBl provided the initial development of the phase curve model. NFS contributed to development of the figures. All authors commented on the manuscript.

show abstract

Inferring heat recirculation and albedo for exoplanetary atmospheres: Comparing optical phase curves and secondary eclipse data

Cited by 20 publications

References 82 publications

Inferring asymmetric limb cloudiness on exoplanets from transit light curves

Inferring asymmetric limb cloudiness on exoplanets from transit light curves

Science Extraction from TESS Observations of Known Exoplanet Hosts

Variability in the atmosphere of the hot giant planet HAT-P-7 b

Contact Info

Product

Resources

About