THERMAL PHASE VARIATIONS OF WASP-12b: DEFYING PREDICTIONS

Cowan, Nicolas B.; Machálek, Pavel; Croll, Bryce; Shekhtman, Louis; Burrows, Adam; Deming, Drake; Greene, T. P.; Hora, J. L.

doi:10.1088/0004-637x/747/1/82

Cited by 205 publications

(309 citation statements)

References 66 publications

(110 reference statements)

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“…These criteria prevent us from over-fitting and are based on the likelihood function given by the χ 2 and on a penalty term related to the number of parameters in the fitting model (Crossfield et al 2012;Cowan et al 2012). The lowest BIC is obtained for the reference model described above (see parameters in Table 3).…”

Section: Resulting Spectramentioning

confidence: 99%

Atmospheric escape from HD 189733b observed in H I Lyman-α: detailed analysis of HST/STIS September 2011 observations

Bourrier

Étangs

Dupuy

et al. 2013

A&A

137

115

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Observations of transits of the hot giant exoplanet HD 189733b in the unresolved H i Lyman-α line show signs of hydrogen escaping the upper atmosphere of the planet. New resolved Lyman-α observations obtained with the STIS spectrograph onboard the Hubble Space Telescope in April 2010 and September 2011 confirmed that the planet is evaporating, and furthermore discovered significant temporal variations in the physical conditions of its evaporating atmosphere. Here we present a detailed analysis of the September 2011 observations of HD 189733b, when an atmospheric signature was detected. We present specific methods to find and characterize this absorption signature of escaping hydrogen in the Lyman-α line, and to calculate its false-positive probability, found to be 3.6%. Taking advantage of the spectral resolution and high sensitivity of the STIS spectrograph, we also present new results on temporal and spectro-temporal variability of this absorption feature. We also report the observation of HD 189733b in other lines (Si iii at 1206.5 Å, N v at 1240 Å). Variations in these lines could be explained either by early occultation by a bow-shock rich in highly ionized species, or by stellar variations.

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Section: Resulting Spectramentioning

confidence: 99%

Atmospheric escape from HD 189733b observed in H I Lyman-α: detailed analysis of HST/STIS September 2011 observations

Bourrier

Étangs

Dupuy

et al. 2013

A&A

137

115

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“…To limit the sample to the most reliable data, we considered only complete transit light curves that were acquired with telescopes with mirrors greater than 1 m. In addition to data from Maciejewski et al (2011) and Maciejewski et al (2013), we used photometric time series from Copperwheat et al (2013), Chan et al (2011), Cowan et al (2012), and Stevenson et al (2014).…”

Section: Observations and Data Processingmentioning

confidence: 99%

Departure from the constant-period ephemeris for the transiting exoplanet WASP-12 b

Maciejewski

Dimitrov

Fernández

et al. 2016

A&A

133

152

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Aims. Most hot Jupiters are expected to spiral in toward their host stars because the angular momentum of the orbital motion is transferred to the stellar spin. Their orbits can also precess as a result of planet-star interactions. Calculations show that both effects might be detected for the very-hot exoplanet WASP-12 b using the method of precise transit-timing over a time span of about 10 yr. Methods. We acquired new precise light curves for 29 transits of WASP-12 b, spannning four observing seasons from November 2012 to February 2016. New mid-transit times, together with those from the literature, were used to refine the transit ephemeris and analyze the timing residuals. Results. We find that the transit times of WASP-12 b do not follow a linear ephemeris with a 5σ confidence level. They may be approximated with a quadratic ephemeris that gives a change rate in the orbital period of (−2.56 ± 0.40) × 10 −2 s yr −1 . The tidal quality parameter of the host star was found to be equal to 2.5 × 10 5 , which is similar to theoretical predictions for Sun-like stars. We also considered a model in which the observed timing residuals are interpreted as a result of the apsidal precession. We find, however, that this model is statistically less probable than the orbital decay.

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“…There have been extensive photometric and spectroscopic studies of WASP-12b (López-Morales et al 2010;Campo et al 2011;Chan et al 2011;Croll et al 2011;Husnoo et al 2011;Maciejewski et al 2011Maciejewski et al , 2013Madhusudhan et al 2011;Cowan et al 2012;Crossfield, Hansen & Barman 2012;Haswell et al 2012;Sada et al 2012;Sokov et al 2012;Southworth et al 2012b;Zhao et al 2012;Copperwheat et al 2013;Crossfield et al 2013;Föhring et al 2013;Fossati et al 2013;Mandell et al 2013;Sing et al 2013;Swain et al 2013;Bechter et al 2014 Table 14. Physical properties of WASP-12b, WASP-33b, WASP-36b, WASP-44b, WASP-48b, and WASP-77Ab derived from the light-curve modelling.…”

Section: Wasp-12bmentioning

confidence: 99%

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

Turner

Pearson

Biddle

et al. 2016

Mon. Not. R. Astron. Soc.

103

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Transits of exoplanets observed in the near-UV have been used to study the scattering properties of their atmospheres and possible star-planet interactions. We observed the primary transits of 15 exoplanets (CoRoT-1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-16b, HAT-P-22b, TrES2b, in the near-UV and several optical photometric bands to update their planetary parameters, ephemerides, search for a wavelength dependence in their transit depths to constrain their atmospheres, and determine if asymmetries are visible in their light curves. Here, we present the first ground-based near-UV light curves for 12 of the targets (CoRoT1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-22b, TrES-2b, TrES-4b, WASP-1b, WASP-33b, WASP-36b, WASP-48b, and WASP-77Ab). We find that none of the near-UV transits exhibit any non-spherical asymmetries, this result is consistent with recent theoretical predictions by Ben-Jaffel et al. and Turner et al. The multiwavelength photometry indicates a constant transit depth from near-UV to optical wavelengths in 10 targets (suggestive of clouds), and a varying transit depth with wavelength in 5 targets (hinting at Rayleigh or aerosol scattering in their atmospheres). We also present the first detection of a smaller near-UV transit depth than that measured in the optical in WASP-1b and a possible opacity source that can cause such radius variations is currently unknown. WASP-36b also exhibits a smaller near-UV transit depth at

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THERMAL PHASE VARIATIONS OF WASP-12b: DEFYING PREDICTIONS

Cited by 205 publications

References 66 publications

Atmospheric escape from HD 189733b observed in H I Lyman-α: detailed analysis of HST/STIS September 2011 observations

Atmospheric escape from HD 189733b observed in H I Lyman-α: detailed analysis of HST/STIS September 2011 observations

Departure from the constant-period ephemeris for the transiting exoplanet WASP-12 b

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

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