THE DEEP BLUE COLOR OF HD 189733b: ALBEDO MEASUREMENTS WITH
                    <i>HUBBLE SPACE TELESCOPE</i>
                    /SPACE TELESCOPE IMAGING SPECTROGRAPH AT VISIBLE WAVELENGTHS

Evans, T. M.; Pont, F.; Sing, David K.; Aigrain, S.; Barstow, Joanna K.; Désert, Jean-Michel; Gibson, Neale P.; Heng, Kevin; Knutson, Heather A.; Étangs, A. Lecavelier des

doi:10.1088/2041-8205/772/2/l16

Cited by 169 publications

(183 citation statements)

References 50 publications

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“…A recent measurement of albedo in the secondary eclipse spectrum of HD189733b (Evans et al 2013) with the STIS on the Hubble Telescope seems to support the haze hypothesis. However a detailed composition and distribution of hazes in atmospheres of the hottest Jupiters is still unclear.…”

Section: The Atmosphere Of Wasp-19bmentioning

confidence: 82%

K s-band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope★

Zhou

Bayliss

Kedziora-Chudczer

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We report new K s band secondary eclipse observations for the hot-Jupiters WASP-19b and WASP-43b. Using the IRIS2 infrared camera on the Anglo-Australian Telescope (AAT), we measured significant secondary eclipses for both planets, with depths of 0.287 +0.020 −0.020 % and 0.181 +0.027 −0.027 % for WASP-19b and WASP-43b respectively. We compare the observations to atmosphere models from the VSTAR line-by-line radiative transfer code, and examine the effect of C/O abundance, top layer haze, and metallicities on the observed spectra. We performed a series of signal injection and recovery exercises on the observed light curves to explore the detection thresholds of the AAT+IRIS2 facility. We find that the optimal photometric precision is achieved for targets brighter than K mag = 9, for which eclipses as shallow as 0.05 % are detectable at > 5 σ significance.

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Section: The Atmosphere Of Wasp-19bmentioning

confidence: 82%

K s-band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope★

Zhou

Bayliss

Kedziora-Chudczer

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…Moreover, literature values suggest that hot Jupiters usually have albedos lower than ∼0.3 (Cowan & Agol 2011). However, several works (e.g., the case of HD 189733b, Evans et al 2013;Pont et al 2013) reported albedo values as high as 0.4-0.5. Such high values may be explained by the scattering of condensates in the high atmosphere (Sudarsky et al 2003).…”

Section: Discussionmentioning

confidence: 99%

“…An interesting result is the observation of HD 189733 b, where researchers were able to infer the planet's color from albedo measurements (Evans et al 2013). Nonetheless, several of these results are still subject to some discussion because it has been shown that the blue excess in the planet's transmission spectrum might also be the result of stellar activity (Oshagh et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Evidence for a spectroscopic direct detection of reflected light from 51 Pegasi b

Martins

Santos

Figueira

et al. 2015

A&A

133

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Context. The detection of reflected light from an exoplanet is a difficult technical challenge at optical wavelengths. Even though this signal is expected to replicate the stellar signal, not only is it several orders of magnitude fainter, but it is also hidden among the stellar noise. Aims. We apply a variant of the cross-correlation technique to HARPS observations of 51 Peg to detect the reflected signal from planet 51 Peg b. Methods. Our method makes use of the cross-correlation function (CCF) of a binary mask with high-resolution spectra to amplify the minute planetary signal that is present in the spectra by a factor proportional to the number of spectral lines when performing the cross correlation. The resulting cross-correlation functions are then normalized by a stellar template to remove the stellar signal. Carefully selected sections of the resulting normalized CCFs are stacked to increase the planetary signal further. The recovered signal allows probing several of the planetary properties, including its real mass and albedo. Results. We detect evidence for the reflected signal from planet 51 Peg b at a significance of 3σ noise . The detection of the signal permits us to infer a real mass of 0.46 +0.06 −0.01 M Jup (assuming a stellar mass of 1.04 M Sun ) for the planet and an orbital inclination of 80 +10 −19 degrees. The analysis of the data also allows us to infer a tentative value for the (radius-dependent) geometric albedo of the planet. The results suggest that 51Peg b may be an inflated hot Jupiter with a high albedo (e.g., an albedo of 0.5 yields a radius of 1.9 ± 0.3 R Jup for a signal amplitude of 6.0 ± 0.4 × 10 −5 ). Conclusions. We confirm that the method we perfected can be used to retrieve an exoplanet's reflected signal, even with current observing facilities. The advent of next generation of instruments (e.g. VLT-ESO/ESPRESSO) and observing facilities (e.g. a new generation of ELT telescopes) will yield new opportunities for this type of technique to probe deeper into exoplanets and their atmospheres.

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“…The presence of non-equilibrium photochemical species with absorption in the blue gives their atmosphere a characteristic red colour (Zahnle et al 2009). The planetary albedo, for instance the observed blue albedo measurement of HD 189733b (Evans et al 2013), could help differentiate between strong Rayleigh scattering dust and red tholin-like species.…”

Section: Introductionmentioning

confidence: 99%

Transmission spectral properties of clouds for hot Jupiter exoplanets

Wakeford

Sing

2015

A&A

184

205

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Clouds play an important role in the atmospheres of planetary bodies. It is expected that, like all the planetary bodies in our solar system, exoplanet atmospheres will also have substantial cloud coverage, and evidence is mounting for clouds in a number of hot Jupiters. To better characterise planetary atmospheres, we need to consider the effects these clouds will have on the observed broadband transmission spectra. Here we examine the expected cloud condensate species for hot Jupiter exoplanets and the effects of various grain sizes and distributions on the resulting transmission spectra from the optical to infrared, which can be used as a broad framework when interpreting exoplanet spectra. We note that significant infrared absorption features appear in the computed transmission spectrum, the result of vibrational modes between the key species in each condensate, which can potentially be very constraining. While it may be hard to differentiate between individual condensates in the broad transmission spectra, it may be possible to discern different vibrational bonds, which can distinguish between cloud formation scenarios, such as condensate clouds or photochemically generated species. Vibrational mode features are shown to be prominent when the clouds are composed of small sub-micron sized particles and can be associated with an accompanying optical scattering slope. These infrared features have potential implications for future exoplanetary atmosphere studies conducted with JWST, where such vibrational modes distinguishing condensate species can be probed at longer wavelengths.

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THE DEEP BLUE COLOR OF HD 189733b: ALBEDO MEASUREMENTS WITH HUBBLE SPACE TELESCOPE /SPACE TELESCOPE IMAGING SPECTROGRAPH AT VISIBLE WAVELENGTHS

Cited by 169 publications

References 50 publications

K s-band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope★

K s-band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope★

Evidence for a spectroscopic direct detection of reflected light from 51 Pegasi b

Transmission spectral properties of clouds for hot Jupiter exoplanets

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