Water vapour absorption in the clear atmosphere of a Neptune-sized exoplanet

Fraine, Jonathan; Deming, Drake; Benneke, Björn; Knutson, Heather A.; Jordán, Andrés; Espinoza, N.; Madhusudhan, Nikku; Wilkins, Ashlee; Todorov, Kamen O.

doi:10.1038/nature13785

Cited by 274 publications

(301 citation statements)

References 41 publications

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“…Following the first detection of an exoplanet atmosphere (Charbonneau et al 2002), secondary eclipse and transit observations have been used to characterize the atmospheres of a number of hot Jupiters (Grillmair et al 2008;Swain et al 2008;Pont et al 2008;Swain et al 2009;Sing et al 2009;Madhusudhan & Seager 2009). More recently, observations have begun to probe new categories of planets, including miniNeptune and super-Earth exoplanets (Stevenson et al 2010;Bean et al 2010;Kreidberg et al 2014;Knutson et al 2014a,b;Ehrenreich et al 2014;Fraine et al 2014). Of course, and as with any young field, some findings remain controversial or have undergone substantial revision Hansen et al 2014;Diamond-Lowe et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Characterizing Rocky and Gaseous Exoplanets with 2 m Class Space-based Coronagraphs

Robinson

Stapelfeldt

Marley

2016

PASP

109

141

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Several concepts now exist for small, space-based missions to directly characterize exoplanets in reflected light. While studies have been performed that investigate the potential detection yields of such missions, little work has been done to understand how instrumental and astrophysical parameters will affect the ability of these missions to obtain spectra that are useful for characterizing their planetary targets. Here, we develop an instrument noise model suitable for studying the spectral characterization potential of a coronagraph-equipped, space-based telescope. We adopt a baseline set of telescope and instrument parameters appropriate for near-future planned missions like WFIRST-AFTA, including a 2 m diameter primary aperture, an operational wavelength range of 0.4-1.0 µm, and an instrument spectral resolution of λ/∆λ = 70, and apply our baseline model to a variety of spectral models of different planet types, including Earth twins, Jupiter twins, and warm and cool Jupiters and Neptunes. With -2 -our exoplanet spectral models, we explore wavelength-dependent planet-star flux ratios for main sequence stars of various effective temperatures, and discuss how coronagraph inner and outer working angle constraints will influence the potential to study different types of planets. For planets most favorable to spectroscopic characterization-cool Jupiters and Neptunes as well as nearby super-Earthswe study the integration times required to achieve moderate signal-to-noise ratio spectra. We also explore the sensitivity of the integration times required to either detect the bottom or presence of key absorption bands (for methane, water vapor, and molecular oxygen) to coronagraph raw contrast performance, exozodiacal light levels, and the distance to the planetary system. Decreasing detector quantum efficiency at longer visible wavelengths makes the detection of water vapor in the atmospheres of Earth-like planets extremely challenging, and also hinders detections of the 0.89 µm methane band. Additionally, most modeled observations have noise dominated by dark current, indicating that improving CCD performance could substantially drive down requisite integration times. Finally, we briefly discuss the extension of our models to a more distant future Large UV-Optical-InfraRed (LUVOIR) mission.

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Section: Introductionmentioning

confidence: 99%

Characterizing Rocky and Gaseous Exoplanets with 2 m Class Space-based Coronagraphs

Robinson

Stapelfeldt

Marley

2016

PASP

109

141

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“…We choose to follow the standard practice of discarding the first orbit as it presents different systematics from the remainder of the data (e.g., Deming et al 2013;Stevenson et al 2014). The raw light curve exhibits a ramp-like increase in flux, commonly referred to as the "hook," with each HST orbit consistent with previous observations (e.g., Berta et al 2012;Deming et al 2013;Fraine et al 2014;Kreidberg et al 2014a). The hook effect, shown in Figure 1 (middle), is generally steeper in the first frame of each HST orbit, so we discard those data points.…”

Section: Band Integrated Light Curvementioning

confidence: 90%

“…Additionally, WASP63b occupies an important, underexplored region of transmission spectroscopy due to its mass. Most exoplanets studied in detail with transmission spectroscopy are either hot Jupiters of mass (∼1-3 M J ) (e.g., Deming et al 2013;Kreidberg et al 2014aKreidberg et al , 2015Sing et al 2016) or Super-Earth-to-Neptune mass planets (∼0.01-0.1 M J ) (e.g., Fraine et al 2014;Knutson et al 2014;Kreidberg et al 2014b). In order to understand formation and evolution processes, it's important to understand the composition of atmospheres over a full and continuous range of masses (e.g., Mordasini et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Community Targets of JWST’s Early Release Science Program: Evaluation of WASP-63b

Kilpatrick

Cubillos

Stevenson

et al. 2018

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We present observations of WASP-63b by the Hubble Space Telescope (HST) as part of "A Preparatory Program to Identify the Single Best Transiting Exoplanet for James Webb Space Telescope (JWST) Early Release Science (ERS)." WASP-63b is one of the community targets under consideration for the JWST ERS program. We present a spectrum derived from a single observation by HST Wide Field Camera3 in the near-infrared. We engaged groups across the transiting exoplanet community to participate in the analysis of the data and present results from each. Extraction of the transmission spectrum by several independent analyses find an H 2 O absorption feature with varying degrees of significance ranging from 1σ to 3σ. The feature, in all cases, is muted in comparison to a clear atmosphere at solar composition. The reasons for the muting of this feature are ambiguous due to a degeneracy between clouds and composition. The data does not yield robust detections of any molecular species other than H 2 O. The group was motivated to perform an additional set of retrieval exercises to investigate an apparent bump in the spectrum at ∼1.55 μm. We explore possible disequilibrium chemistry and find this feature is consistent with super-solar HCN abundance but it is questionable if the required mixing ratio of HCN is chemically and physically plausible. The ultimate goal of this study is to vet WASP-63b as a potential community target to best demonstrate the capabilities and systematics of JWST instruments for transiting exoplanet science. In the case of WASP-63b, the presence of a detectable water feature indicates that WASP-63b remains a plausible target for JWST observations.

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“…In the case of HAT-P-11b, Kepler observations were useful in characterizing the activity of the K-type host star; and the analysis of crossing stellar spots allowed the determination of the spin-orbit misalignment of this system (Deming et al 2011;Sanchis-Ojeda & Winn 2011). Simultaneous observations of the transits of HAT-P-11b by Kepler and Spitzer allowed also the detection of water vapor in the atmosphere of this Neptune-size planet (Fraine et al 2014). Estimation of the planetary physical parameters depend strongly on the estimated stellar properties.…”

Section: Introductionmentioning

confidence: 99%

HATS9-b AND HATS10-b: TWO COMPACT HOT JUPITERS IN FIELD 7 OF THE K2 MISSION

Brahm

Jordán

Hartman

et al. 2015

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We report the discovery of two transiting extrasolar planets by the HATSouth survey. HATS-9b orbits an old (10.8 ± 1.5 Gyr) V=13.3 G dwarf star, with a period P ≈ 1.9153 d. The host star has a mass of 1.03 M , radius of 1.503R and effective temperature 5366 ± 70 K. The planetary companion has a mass of 0.837 M J , and radius of 1.065 R J yielding a mean density of 0.85 g cm −3 . HATS-10b orbits a V=13.1 G dwarf star, with a period P ≈ 3.3128 d. The host star has a mass of 1.1 M , radius of 1.11 R and effective temperature 5880 ± 120 K. The planetary companion has a mass of 0.53 M J , and radius of 0.97 R J yielding a mean density of 0.7 g cm −3 . Both planets are compact in comparison with planets receiving similar irradiation from their host stars, and lie in the nominal coordinates of Field 7 of K2 but only HATS-9b falls on working silicon. Future characterization of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature.

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Water vapour absorption in the clear atmosphere of a Neptune-sized exoplanet

Cited by 274 publications

References 41 publications

Characterizing Rocky and Gaseous Exoplanets with 2 m Class Space-based Coronagraphs

Characterizing Rocky and Gaseous Exoplanets with 2 m Class Space-based Coronagraphs

Community Targets of JWST’s Early Release Science Program: Evaluation of WASP-63b

HATS9-b AND HATS10-b: TWO COMPACT HOT JUPITERS IN FIELD 7 OF THE K2 MISSION

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