Detection of atmospheric haze on an extrasolar planet: the 0.55–1.05 μm transmission spectrum of HD 189733b with the Hubble Space Telescope

By F. Pont, H. Knutson, R. Gilliland, C. Moutou, D. Charbonneau. 2007

398 citations recorded by the source corpus.

The nearby transiting planet HD 189733b was observed during three transits with the Advanced Camera for Surveys of the Hubble Space Telescope in spectroscopic mode. The resulting time-series of 675 spectra covers the 550–1050 nm range, with a resolution element of ∼8 nm, at extremely high accuracy (signal-to-noise ratio up to 10 000 in 50-nm intervals in each individual spectrum). Using these data, we disentangle the effects of limb darkening, measurement systematics and spots on the surface of the host star, to calculate the wavelength dependence of the effective transit radius to an accuracy of ∼50 km. This constitutes the ‘transmission spectrum’ of the planetary atmosphere. It indicates at each wavelength at what height the planetary atmosphere becomes opaque to the grazing stellar light during the transit. In this wavelength range, strong features due to sodium, potassium and water are predicted by atmosphere models for a planet like HD 189733b, but they can be hidden by broad absorption from clouds or hazes higher up in the atmosphere. We observed an almost featureless transmission spectrum between 550 and 1050 nm, with no indication of the expected sodium or potassium atomic absorption features. Comparison of our results with the transit radius observed in the near and mid-infrared (2–8 μm), and the slope of the spectrum, suggest the presence of a haze of submicrometre particles in the upper atmosphere of the planet.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/2419f647e3094c5ba62801e6fb459bb2cf373c2a

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In Aerospace Engineering

1. N. Madhusudhan
2. D. Sing
3. D. Deming
4. J. D'esert
5. Jon Fortney
6. Sara Seager
7. A. Vidal-Madjar
8. G. Henry

In Astronomy and Astrophysics

1. N. Madhusudhan
2. Jon Fortney
3. A. Showman
4. D. Sing
5. D. Deming
6. H. Knutson
7. D. Charbonneau
8. Sara Seager

In Atomic and Molecular Physics, and Optics

1. D. Sing
2. D. Deming
3. Jon Fortney
4. J. D'esert
5. D. Charbonneau
6. Sara Seager
7. A. Vidal-Madjar
8. G. Henry

Citations in the corpus

• Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS (2009, methodology): “A transit light curve is affected by the presence of star spots, both when a spot is occulted by the planet and by the presence of non-occulted spots during the epoch of the transit observations (Pont et al. 2008).”
• SEARCH FOR CARBON MONOXIDE IN THE ATMOSPHERE OF THE TRANSITING EXOPLANET HD 189733b (2009, methodology): “Using the Advanced Camera for Survey aboard the Hubble Space Telescope (HST), Pont et al. (2008) detected atmospheric haze interpreted as Mie scattering by small particles (Lecavelier des Etangs et al. 2008a).”
• DETECTION OF H2O AND EVIDENCE FOR TiO/VO IN AN ULTRA-HOT EXOPLANET ATMOSPHERE (2016, background): “Transmission spectra at optical wavelengths show evidence for Rayleigh scattering by molecular hydrogen and high-altitude aerosols, and absorption by alkali metals (e.g. Charbonneau et al. 2002; Pont et al. 2008; Sing et al. 2013, 2015; Nikolov et al. 2014, 2015).”
• THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE (2011, methodology): “This is unlike the case of the hot Jupiter HD189733b, where the uniform decrease in transit depth from 0.3 to 1 µm (Pont et al. 2008; Lecavelier Des Etangs et al. 2008; Sing et al. 2011) and perhaps to as far as 3.6 µm (see Sing et al. 2009; Désert et al. 2009) has been convincingly attributed to…”
• Detection of water absorption in the day side atmosphere of HD 189733 b using ground-based high-resolution spectroscopy at 3.2 μm (2013, background): “…b is one of the most studied exoplanets to date, with strong evidence for a high-altitude haze that causes Rayleigh scattering from 0.3 to 1 µm (Pont et al. 2008; Sing et al. 2009, 2011; Pont et al. 2013), reports of H2O absorption features at infrared wavelengths (Tinetti et al. 2007;…”
• A TEMPERATURE AND ABUNDANCE RETRIEVAL METHOD FOR EXOPLANET ATMOSPHERES (2009, background): “…2006); spectral features in transmission dominated by molecular absorption over cloud particles (Showman et al. 2009 and references therein); haze absorption at blue wavelengths on HD 189733b drops off rapidly with increasing wavelength and should be negligible at IR wavelengths (Pont et al. 2008).”
• Exoplanet Atmospheres: Physical Processes (2010, methodology): “While the particle composition has not been identified, the Rayleigh-scattering behavior of the data indicates small particle sizes (Pont et al. 2008).”
• Evaporation of the planet HD 189733b observed in H I Lyman-α (2010, methodology): “Using HST/ACS, Pont et al. (2008) detected atmospheric haze, which is interpreted as Mie scattering by small particles (Lecavelier des Etangs et al. 2008b).”
• Optimal estimation retrievals of the atmospheric structure and composition of HD 189733b from secondary eclipse spectroscopy (2011, methodology): “…metal sodium were reported using observations with the high resolution ground spectrograph of theHobby–Eberly Telescope (Redfield et al. 2008), while featureless spectra detected by theHST /ACS (Pont et al. 2008) andHST /STIS (Sing et al. 2011) are thought to be caused by thick atmospheric hazes.”
• 3.6 AND 4.5 μm PHASE CURVES AND EVIDENCE FOR NON-EQUILIBRIUM CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HD 189733b (2012, methodology): “…these variations are reduced in the infrared, they are still comparable to the planet’s phase curve and must be accounted for in our estimates of the phase curve amplitude (Knutson et al. 2009a) and wavelength-dependent transit depth (Pont et al. 2008; Désert et al. 2009, 2011a; Sing et al. 2011).”
• ATMOSPHERIC CIRCULATION OF HOT JUPITERS: COUPLED RADIATIVE-DYNAMICAL GENERAL CIRCULATION MODEL SIMULATIONS OF HD 189733b and HD 209458b (2008, neutral): “The situation is less clear at visible wavelengths (Pont et al. 2008; Redfield et al. 2008), but submicron-sized haze particles ara possibility.”
• Detection of carbon monoxide in the high-resolution day-side spectrum of the exoplanet HD 189733b (2013, background): “Hence, we conclude that the haze layer seen by Pont et al. (2008); Sing et al. (2009); Pont et al. (2012) is either optically thin when seen at normal incidence angles and that consequently there is no temperature inversion in the middle atmosphere, or that the haze layer is optically thick, but…”
• An HST optical-to-near-IR transmission spectrum of the hot Jupiter WASP-19b: detection of atmospheric water and likely absence of TiO (2013, background): “…radius with decreasing wavelength, attributed to a scattering signature similar to that of Rayleigh scattering (Lecavelier Des Etangs et al. 2008; Pont et al. 2008; Sing et al. 2011a), where all but the narrow cores of the lines are obscured (Redfield et al. 2008; Jensen et al. 2011; Huitson et…”
• WATER VAPOR IN THE SPECTRUM OF THE EXTRASOLAR PLANET HD 189733b. I. THE TRANSIT (2014, background): “This procedure is consistent with similar previous work (e.g., Pont et al. 2008, 2013; Sing et al. 2011).”
• A Gaussian process framework for modelling instrumental systematics: application to transmission spectroscopy (2011, methodology): “All non-variable parameters were fixed to the values given in Pont et al. (2008), except for the limb darkening parameters, which were calculated for each wavelength channel (GPA11, Sing 2010).”
• Hubble Space Telescope STIS Optical Transit Transmission Spectra of the Hot Jupiter HD 209458b (2008, methodology): “The success of using Atlas models in analyzing transits of the K0 V star HD189733 (Pont et al. 2007), further highlights their capabilities.”
• MULTIWAVELENGTH CONSTRAINTS ON THE DAY–NIGHT CIRCULATION PATTERNS OF HD 189733b (2008, methodology): “This planet has a mass of 1.14±0.06 MJup (Bouchy et al. 2005; Torres et al. 2008) and a radius of 1.138±0.027RJup (Bakos et al. 2006b; Winn et al. 2007a; Knutson et al. 2007; Pont et al. 2007, 2008; Torres et al. 2008), and orbits a K0V primary with a V -band magnitude of 7.67 (Bouchy et al. 2005).”
• Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b (2013, background): “…spectrum of HD 189733b is described by an increasing planetary radius with decreasing wavelength, most likely due to Rayleigh scattering (Pont et al. 2008; Sing et al. 2009, 2011b; Lecavelier Des Etangs et al. 2008) and presence of narrow line cores of sodium peaking above the slope…”