<i>SPITZER</i>SECONDARY ECLIPSES OF THE DENSE, MODESTLY-IRRADIATED, GIANT EXOPLANET HAT-P-$20{\rm b}$ USING PIXEL-LEVEL DECORRELATION

Deming, Drake; Knutson, Heather A.; Kammer, Joshua A.; Fulton, Benjamin J.; Ingalls, James G.; Carey, Sean; Burrows, Adam; Fortney, Jonathan J.; Todorov, Kamen O.; Agol, Eric; Cowan, Nicolas B.; Désert, Jean Michel; Fraine, Jonathan; Langton, Jonathan; Morley, Caroline; Showman, Adam P.

doi:10.1088/0004-637x/805/2/132

Cited by 271 publications

(341 citation statements)

References 53 publications

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“…A usual method is to detrend the measured flux from the X/Y position of the centroid, using quadratic order polynomial functions. In the past years, several studies (Ballard et al 2010;Stevenson et al 2012;Lewis et al 2013;Deming et al 2014) have employed novel techniques that improved the mitigation of the intra-pixel sensitivity in Spitzer/IRAC 3.6 and 4.5µm channels.…”

Section: Intra-pixel Sensitivity Correctionmentioning

confidence: 99%

Variability in the super-Earth 55 Cnc e

Demory

Gillon

Madhusudhan

et al. 2015

Mon. Not. R. Astron. Soc.

158

147

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Considerable progress has been made in recent years in observations of atmospheric signatures of giant exoplanets, but processes in rocky exoplanets remain largely unknown due to major challenges in observing small planets. Numerous efforts to observe spectra of superEarths, exoplanets with masses of 1-10 Earth masses, have thus far revealed only featureless spectra. In this paper we report a 4-σ detection of variability in the dayside thermal emission from the transiting super-Earth 55 Cancri e. Dedicated space-based monitoring of the planet in the mid-infrared over eight eclipses revealed the thermal emission from its dayside atmosphere varying by a factor 3.7 between 2012 and 2013. The amplitude and trend of the variability are not explained by potential influence of star spots or by local thermal or compositional changes in the atmosphere over the short span of the observations. The possibility of large scale surface activity due to strong tidal interactions possibly similar to Io, or the presence of circumstellar/circumplanetary material appear plausible and motivate future long-term monitoring of the planet.

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Section: Intra-pixel Sensitivity Correctionmentioning

confidence: 99%

Variability in the super-Earth 55 Cnc e

Demory

Gillon

Madhusudhan

et al. 2015

Mon. Not. R. Astron. Soc.

158

147

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“…We correct for this effect using pixellevel decorrelation (PLD), as described by Deming et al (2015). This method models the variation in flux intensity in each image due to this instrumental effect by tracking the change in intensity over time within a small box of pixels centered on the flux-weighted centroid.…”

Section: Instrumental Noise Model and Optimal Aperture Selectionmentioning

confidence: 99%

“…We divide the flux in each individual pixel by the summed flux across all 9pixels, weighting each pixel by its contribution to the flux and thereby isolating the instrument noise from astrophysical signals(see Deming et al 2015), and werepeat this operation for each image in our photometric time series. We also incorporate a constant and a linear term in time to model baseline instrument noise.…”

Section: Instrumental Noise Model and Optimal Aperture Selectionmentioning

confidence: 99%

“…We also incorporate a constant and a linear term in time to model baseline instrument noise. Unlike Deming et al (2015), we do not include a quadratic term because we found that the linear fit has an equivalent rms residualto the quadratic fit, and so adding the quadratic parameter is not justified. In addition, the quadratic term was correlated with the eclipse depth in our model fits.…”

Section: Instrumental Noise Model and Optimal Aperture Selectionmentioning

confidence: 99%

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Dynamical Constraints on the Core Mass of Hot Jupiter Hat-P-13b

Buhler

Knutson

Batygin

et al. 2016

ApJ

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HAT-P-13b is a Jupiter-mass transiting exoplanet that has settled onto a stable, short-period, and mildly eccentric orbit as a consequence of the action of tidal dissipation and perturbations from a second, highly eccentric, outer companion. Owingto the special orbital configuration of the HAT-P-13 system, the magnitude of HAT-P-13bʼs eccentricity (e b ) is in part dictated by its Love number (k 2 b ), which is in turn a proxy for the degree of central mass concentration in its interior. Thus, the measurement of e b constrains k 2 b and allows us to place otherwise elusive constraints on the mass of HAT-P-13bʼs core (M core,b ). In this study we derive new constraints on the value of e b by observing two secondary eclipses of HAT-P-13b with the Infrared Array Camera on board the Spitzer Space Telescope. We fit the measured secondary eclipse times simultaneously with radial velocity measurements and find that e b =0.00700±0.00100. We then use octupole-order secular perturbation theory to find the corresponding = Applying structural evolution models, we then find, with 68% confidence, that M core,b is less than 25 Earth masses (M ⊕ ). The most likely value isM core,b =11 M ⊕ , which is similar to the core mass theoretically required for runaway gas accretion. This is the tightest constraint to date on the core mass of a hot Jupiter. Additionally, we find that the measured secondary eclipse depths, which are in the 3.6 and 4.5 μm bands, best match atmospheric model predictions with a dayside temperature inversion and relatively efficient day-night circulation.

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“…During the modeling, the orbital period of HAT-P-20b is fixed to the value derived by Granata et al (2014), and the search intervals of u 1 and u 2 are set to (u 1c −0.05, u 1c +0.05) and (0.1, 0.3), respectively, where u 1c denotes the values interpolated from Claret (2000Claret ( , 2004's table based on the stellar parameters derived by Bakos et al (2011). The Gaussian penalties of e and ω are set to the best estimations and uncertainties of Deming et al (2015) derived from simultaneously modeling transits, secondary eclipses, and radial velocity data of HAT-P-20, through which the most accurate e and ω could be obtained. We check the posterior probability distributions of several main transit parameters and confirm the convergence of the solution through the fact that the majority of these models have similar distributions for these parameters.…”

Section: Initial Analysismentioning

confidence: 99%

Refined System Parameters and TTV Study of Transiting Exoplanetary System Hat-P-20

Sun

Wang

et al. 2016

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We report new photometric observations of the transiting exoplanetary system HAT-P-20, obtained using CCD cameras at Yunnan Observatories and Ho Koon Nature Education cum Astronomical Centre, China, from 2010 to 2013, and Observatori Ca l'Ou, Sant Marti Sesgueioles, Spain, from 2013 to 2015. The observed data are corrected for systematic errors according to the coarse de-correlation and SYSREM algorithms, so as to enhance the signal of the transit events. In order to consistently model the star spots and transits of this exoplanetary system, we develop a highly efficient tool STMT based on the analytic models of Mandel & Agol and Montalto et al. The physical parameters of HAT-P-20 are refined by homogeneously analyzing our new data, the radial velocity data, and the earlier photometric data in the literature with the Markov chain Monte Carlo technique. New radii and masses of both host star and planet are larger than those in the discovery paper due to the discrepancy of the radius among K-dwarfs between predicted values by standard stellar models and empirical calibration from observations. Through the analysis of all available mid-transit times calculated with the normal model and spotted model, we conclude that the periodic transit timing variations in these transit events revealed by employing the normal model are probably induced by spot crossing events. From the analysis of the distribution of occulted spots by HAT-P20b, we constrain the misaligned architecture between the planetary orbit and the spin of the host star.

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SPITZERSECONDARY ECLIPSES OF THE DENSE, MODESTLY-IRRADIATED, GIANT EXOPLANET HAT-P-$20{\rm b}$ USING PIXEL-LEVEL DECORRELATION

Cited by 271 publications

References 53 publications

Variability in the super-Earth 55 Cnc e

Variability in the super-Earth 55 Cnc e

Dynamical Constraints on the Core Mass of Hot Jupiter Hat-P-13b

Refined System Parameters and TTV Study of Transiting Exoplanetary System Hat-P-20

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