Combining Photometry from<i>Kepler</i>and<i>TESS</i>to Improve Short-period Exoplanet Characterization

Placek, Ben; Knuth, Kevin H.; Angerhausen, Daniel

doi:10.1088/1538-3873/128/965/074503

Cited by 34 publications

(22 citation statements)

References 40 publications

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“…We suggest that by comparing CHEOPS and TESS geometric albedos, qualitative information about the cloud particles of an exoplanet can be derived. A similar suggestion was stated by Placek et al (2016) which modelled disentangling scattered and emitted components from a combined Kepler and TESS photometry for revisited Kepler field planets. If the CHEOPS band is brighter than the TESS bandpass, our modelling suggests that an optical wavelength scattering cloud particle is present.…”

Section: Discussionsupporting

confidence: 73%

Dynamic mineral clouds on HD 189733b

Lee

Wood

Dobbs-Dixon

et al. 2017

A&A

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Context. As the 3D spatial properties of exoplanet atmospheres are being observed in increasing detail by current and new generations of telescopes, the modelling of the 3D scattering effects of cloud forming atmospheres with inhomogeneous opacity structures becomes increasingly important to interpret observational data. Aims. We model the scattering and emission properties of a simulated cloud forming, inhomogeneous opacity, hot Jupiter atmosphere of HD 189733b. We compare our results to available Hubble Space Telescope (HST) and Spitzer data and quantify the effects of 3D multiple scattering on observable properties of the atmosphere. We discuss potential observational properties of HD 189733b for the upcoming Transiting Exoplanet Survey Satellite (TESS) and CHaracterising ExOPlanet Satellite (CHEOPS) missions. Methods. We developed a Monte Carlo radiative transfer code and applied it to post-process output of our 3D radiative-hydrodynamic, cloud formation simulation of HD 189733b. We employed three variance reduction techniques, i.e. next event estimation, survival biasing, and composite emission biasing, to improve signal to noise of the output. For cloud particle scattering events, we constructed a log-normal area distribution from the 3D cloud formation radiative-hydrodynamic results, which is stochastically sampled in order to model the Rayleigh and Mie scattering behaviour of a mixture of grain sizes. Results. Stellar photon packets incident on the eastern dayside hemisphere show predominantly Rayleigh, single-scattering behaviour, while multiple scattering occurs on the western hemisphere. Combined scattered and thermal emitted light predictions are consistent with published HST and Spitzer secondary transit observations. Our model predictions are also consistent with geometric albedo constraints from optical wavelength ground-based polarimetry and HST B band measurements. We predict an apparent geometric albedo for HD 189733b of 0.205 and 0.229, in the TESS and CHEOPS photometric bands respectively. Conclusions. Modelling the 3D geometric scattering effects of clouds on observables of exoplanet atmospheres provides an important contribution to the attempt to determine the cloud properties of these objects. Comparisons between TESS and CHEOPS photometry may provide qualitative information on the cloud properties of nearby hot Jupiter exoplanets.

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Section: Discussionsupporting

confidence: 73%

Dynamic mineral clouds on HD 189733b

Lee

Wood

Dobbs-Dixon

et al. 2017

A&A

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“…A good example of the above is the Kepler-13A (KOI-13, KIC 9941662) system, containing an A type host star and a short period (1.76 day) massive gas giant planet Szabó et al 2011;Mazeh et al 2012;Mislis & Hodgkin 2012;Esteves et al 2013;Placek et al 2014). The transit was detected in Kepler data but the star's fast rotation (V sin(I) = 76.6 ± 0.2 km s −1 , Johnson et al 2014) prevents obtaining RVs precise enough to detect the star's orbital motion induced by the transiting companion, as shown by Santerne et al (2012) who were only able to place an upper limit on the RV variability.…”

Section: Astrophysical Uses Of Optical Phase Curvesmentioning

confidence: 99%

“…Kepler-13A is the transiting planet host and Kepler-13B hosts a non-eclipsing stellar companion (Kepler-13BC) on a 65.8 day orbit (Santerne et al 2012;Johnson et al 2014). Esteves et al 2013;Placek et al 2014;Shporer et al 2014;Esteves et al 2015) who used the amplitudes of the two gravitational phase components, the beaming effect and the tidal ellipsoidal distortion, to estimate the transiting companion's mass. There are several factors that contribute to the uncertainty on the derived mass using this method:…”

Section: Astrophysical Uses Of Optical Phase Curvesmentioning

confidence: 99%

The Astrophysics of Visible-light Orbital Phase Curves in the Space Age

Shporer

2017

PASP

130

107

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The field of visible-light continuous time series photometry is now at its golden age, manifested by the continuum of past (CoRoT, Kepler), present (K2), and future (TESS, PLATO) space-based surveys delivering high precision data with a long baseline for a large number of stars. The availability of the high quality data has enabled astrophysical studies not possible before, including for example detailed asteroseismic investigations and the study of the exoplanet census including small planets. This has also allowed to study the minute photometric variability following the orbital motion in stellar binaries and star-planet systems which is the subject of this review. We focus on systems with a main sequence primary and a low-mass secondary, from a small star to a massive planet. The orbital modulations are induced by a combination of gravitational and atmospheric processes, including the beaming effect, tidal ellipsoidal distortion, reflected light, and thermal emission. Therefore, the phase curve shape contains information about the companion's mass and atmospheric characteristics, making phase curves a useful astrophysical tool. For example, phase curves can be used to detect and measure the mass of short-period low-mass companions orbiting hot fast-rotating stars, out of reach of other detection methods. Another interesting application of phase curves is using the orbital phase modulations to look for non-transiting systems, which comprise the majority of stellar binary and star-planet systems. We discuss the science done with phase curves, the first results obtained so far, and the current difficulties and open questions related to this young and evolving subfield.

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“…Models used to characterize self-luminous planets so far have not considered the effects of optical stellar irradiation and reflection, because the objects observed to date are on very wide orbits, and are observed at NIR wavelengths, where reflected light's contribution is negligible. The only measurements made of exoplanet optical albedos have come from phase curves of hot Jupiters (Placek et al 2016). Optical phase curves are available from Kepler and K2 (Esteves et al 2015), and many more will be collected by TESS (Mayorga et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Prospects for Directly Imaging Young Giant Planets at Optical Wavelengths

Lacy

Burrows

2020

ApJ

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In this work, we investigate the properties of young giant planet spectra in the optical and suggest that future space-based direct imaging missions should be considering young planets as a valuable and informative science case. While young planets are dimmer in the optical than in the infrared, they can still be brighter in the optical than a mature planet of similar mass. Therefore, an instrument designed to characterize mature planets should also be suitable for high-precision photometric imaging and spectroscopy of young self-luminous planets in a wavelength range and at a contrast ratio not attainable from the ground. We identify known young self-luminous companions which are feasible targets for WFIRST-CGI and compute spectra for them, including a treatment of scattering and reflected light at optical wavelengths. Using these results, we highlight potentially diagnostic spectral features that will be present in the WFIRST-CGI wavelengths. Expanding to direct imaging missions beyond WFIRST-CGI, we also use evolutionary models across a grid of masses and planet-star separations as inputs to compute spectra of hypothetical objects, exploring when reflected light may contribute to a degree comparable to that of thermal emission from the residual heat of formation.

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Combining Photometry fromKeplerandTESSto Improve Short-period Exoplanet Characterization

Cited by 34 publications

References 40 publications

Dynamic mineral clouds on HD 189733b

Dynamic mineral clouds on HD 189733b

The Astrophysics of Visible-light Orbital Phase Curves in the Space Age

Prospects for Directly Imaging Young Giant Planets at Optical Wavelengths

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