Further constraints on the optical transmission spectrum of HAT-P-1b

Abstract

We report on novel observations of HAT-P-1 aimed at constraining the optical transmission spectrum of the atmosphere of its transiting Hot-Jupiter exoplanet. Ground-based differential spectrophotometry was performed over two transit windows using the DOLORES spectrograph at the Telescopio Nazionale Galileo (TNG). Our measurements imply an average planet to star radius ratio equal to ${\mathrm{R}}_{\mathrm{p}}/{\mathrm{R}}_{\star }$=(0.1159$\pm$0.0005). This result is consistent with the value obtained from recent near infrared measurements of this object but differs from previously reported optical measurements being lower by around 4.4 exoplanet scale heights. Analyzing the data over 5 different spectral bins 600Å wide we observed a single peaked spectrum (3.7 $\sigma$ level) with a blue cut-off corresponding to the blue edge of the broad absorption wing of sodium and an increased absorption in the region in between 6180-7400Å. We also infer that the width of the broad absorption wings due to alkali metals is likely narrower than the one implied by solar abundance clear atmospheric models. We interpret the result as evidence that HAT-P-1b has a partially clear atmosphere at optical wavelengths with a more modest contribution from an optical absorber than previously reported.

Accepted by ApJ

References in corpus (17)

• The effect of red noise on planetary transit detection
• Sodium Absorption From the Exoplanetary Atmosphere of HD189733b Detected in the Optical Transmission Spectrum
• Atmospheric Sulfur Photochemistry on Hot Jupiters
• Theoretical Spectra and Light Curves of Close-in Extrasolar Giant Planets and Comparison with Data
• Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands
• Ground-based detection of sodium in the transmission spectrum of exoplanet HD209458b
• Limb darkening and exoplanets: testing stellar model atmospheres and identifying biases in transit parameters
• HAT-P-1b: A Large-Radius, Low-Density Exoplanet Transiting one Member of a Stellar Binary
• HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and Rayleigh scattering
• New Analysis Indicates No Thermal Inversion in the Atmosphere of HD 209458b
• TiO and VO broad band absorption features in the optical spectrum of the atmosphere of the hot-Jupiter HD209458b
• Impact of occultations of stellar active regions on transmission spectra: Can occultation of a plage mimic the signature of a blue sky?
• A uniform analysis of HD209458b Spitzer/IRAC lightcurves with Gaussian process models
• Properties of analytic transit light curve models
• The Transit Light Curve Project. VII. The Not-So-Bloated Exoplanet HAT-P-1b
• Measurement of the Spin-Orbit Angle of Exoplanet HAT-P-1b
• GTC OSIRIS transiting exoplanet atmospheric survey: detection of potassium in HAT-P-1b from narrowband spectrophotometry

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• A large range of haziness conditions in hot-Jupiter atmospheres
• Ground-based optical transmission spectrum of the hot Jupiter HAT-P-1b
• Detection of Na and K in the atmosphere of the hot Jupiter HAT-P-1b with P200/DBSP
• Looking For Timing Variations in the Transits of 16 Exoplanets
• A Population Analysis of 20 Exoplanets Observed from the Optical to the Near-infrared Wavelengths with HST: Evidence for Widespread Stellar Contamination
• Low-resolution Transit Spectroscopy of Three Hot Jupiters Using the 2m Himalayan Chandra Telescope